ADS1283IRHFT [TI]
用于地震监测和能源勘探且具有 PGA 的超高分辨率 4kSPS 2 通道 Δ-Σ ADC | RHF | 24 | -40 to 85;型号: | ADS1283IRHFT |
厂家: | TEXAS INSTRUMENTS |
描述: | 用于地震监测和能源勘探且具有 PGA 的超高分辨率 4kSPS 2 通道 Δ-Σ ADC | RHF | 24 | -40 to 85 转换器 |
文件: | 总68页 (文件大小:2237K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
Support &
Community
Product
Folder
Order
Now
Tools &
Software
Technical
Documents
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
ADS1283 高分辨率模数转换器
1 特性
3 说明
1
•
•
•
高分辨率:
ADS1283 是一款性能极高的单芯片模数转换器
(ADC),配备集成式低噪声可编程增益放大器 (PGA)
和双通道输入多路复用器 (MUX)。ADS1283 可满足地
震监测设备的严苛要求。
–
SNR:130 dB(250 SPS,PGA = 1)
高精度:
–
THD:–122dB
低功耗:
此转换器使用一个固有稳定性的四阶 Δ-Σ 调制器来获
得出色的抗噪性能和线性性能。调制器数字输出由片上
数字滤波器进行数字过滤和抽取,以生成 ADC 转换结
果。
–
–
18mW(PGA = 1、2、4 或 8)
停机模式:10μW
•
•
•
•
低噪声 PGA:5nV/√Hz
双通道输入多路复用器
输入多路复用器可灵活提供附加的外部输入,用于测量
以及内部自检输入连接。PGA 具有 出色的低噪声
(5nV/√Hz) 和极高的输入阻抗,便于轻松连接到具有宽
增益范围的地震检波器和水听器。
固有稳定性的调制器,具有快速响应超范围检测器
灵活的数字滤波器:
–
正弦 + 有限脉冲响应 (FIR) + 无限脉冲响应
(IIR)(可选)
–
–
–
线性或最小相位响应
可编程的高通滤波器
数字滤波器提供 250SPS 至 4000SPS 的可选数据速
率。高通滤波器 (HPF) 具有 可调节的角频率。片上增
益和偏移调节寄存器支持系统校准。
可选择 FIR 数据速率:
250SPS 至 4kSPS
同步输入 (SYNC) 可用来使多个 ADS1283 器件的转换
同步。
•
•
•
•
偏移和增益校准引擎
SYNC 输入
模拟电源:5V 或 ±2.5V
数字电源:1.8V 至 3.3V
ADS1283 采用紧凑的 24 引线 5mm x 4 mm VQFN 封
装,完全额定工作温度为 –40°C 至 +85°C,最大工作
温度范围为 –50°C 至 +125°C。
2 应用
器件信息(1)
•
•
•
能量勘探
器件型号
ADS1283
封装
封装尺寸(标称值)
地震监测
高精度仪器
ADS1283A
ADS1283B
VQFN (24)
5.00mm × 4.00mm
简化电路原理图
AVDD
VREFN
DVDD
VREFP
(1) 如需了解所有可用封装,请参阅产品说明书末尾的封装选项附
录。
CLK
CS
4th-Order
ûꢀ
Modulator
Programmable
Digital
Filter
Input 1
Input 2
SCLK
DOUT
DIN
Serial
Interface
器件比较
Calibration
PGA
THD(典型
VCOM
器件型号
ADS1283
失调电压选项
增益
值)
–122dB
–118dB
–122dB
DRDY
SYNC
Overrange
Control
100mV
1 至 64
1、4、16
1 至 64
RESET
PWDN
ADS1283
ADS1283A
ADS1283B
100mV
AVSS
DGND
75mV、100mV
1
本文档旨在为方便起见,提供有关 TI 产品中文版本的信息,以确认产品的概要。 有关适用的官方英文版本的最新信息,请访问 www.ti.com,其内容始终优先。 TI 不保证翻译的准确
性和有效性。 在实际设计之前,请务必参考最新版本的英文版本。
English Data Sheet: SBAS565
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
目录
8.1 Overview ................................................................. 15
8.2 Functional Block Diagram ....................................... 16
8.3 Feature Description................................................. 16
8.4 Device Functional Modes........................................ 32
8.5 Programming........................................................... 44
8.6 Register Maps......................................................... 48
Application and Implementation ........................ 52
9.1 Application Information............................................ 52
9.2 Typical Applications ................................................ 52
9.3 Initialization Set Up ................................................. 55
1
2
3
4
5
6
特性.......................................................................... 1
应用.......................................................................... 1
说明.......................................................................... 1
修订历史记录 ........................................................... 2
Pin Configuration and Functions......................... 4
Specifications......................................................... 5
6.1 Absolute Maximum Ratings .................................... 5
6.2 ESD Ratings.............................................................. 5
6.3 Recommended Operating Conditions....................... 5
6.4 Thermal Information.................................................. 6
6.5 Electrical Characteristics........................................... 6
6.6 Timing Requirements............................................... 9
6.7 Switching Characteristics.......................................... 9
6.8 Typical Characteristics............................................ 10
Parameter Measurement Information ................ 14
7.1 Noise Performance ................................................. 14
Detailed Description ............................................ 15
9
10 器件和文档支持 ..................................................... 56
10.1 接收文档更新通知 ................................................. 56
10.2 社区资源................................................................ 56
10.3 商标....................................................................... 56
10.4 静电放电警告......................................................... 56
10.5 Glossary................................................................ 56
11 机械、封装和可订购信息....................................... 57
7
8
4 修订历史记录
注:之前版本的页码可能与当前版本有所不同。
Changes from Revision B (December 2017) to Revision C
Page
•
已更改 将文档更改为面向 Web 的完整发布版........................................................................................................................ 1
Changes from Revision A (May 2015) to Revision B
Page
•
•
•
已添加 ADS1283B 器件及相关内容添加到产品说明书 ........................................................................................................... 1
已添加 器件信息和器件比较表................................................................................................................................................ 1
Added Recommended Operating Conditions table; content moved from Electrical Characteristics table. No values
changed.................................................................................................................................................................................. 5
•
•
•
•
•
•
•
•
•
•
•
•
Deleted ADS1283A text from test condition in Electrical Characteristic table........................................................................ 6
Added new row for ADS1283B test condition to Offset parameter in the Electrical Characteristics table............................. 7
Added Switching Characteristics table; content moved from Timing Requirements table. No values changed.................... 9
Changed text in Offset section for 75-mV option ................................................................................................................. 22
Changed Figure 45 to include CLK to SYNC timing ............................................................................................................ 32
Deleted tCSHD and tSCSU from Table 12 ................................................................................................................................ 32
Added CLK to SYNC timing to Table 12 .............................................................................................................................. 32
Changed text in last paragraph of Pulse-Sync Mode section ............................................................................................. 33
Changed pulse-sync timing text to include CLK to SYNC timing ........................................................................................ 33
Changed Figure 46 to include CLK to SYNC timing ........................................................................................................... 33
Changed opcode text of WREG command from 001 to 010 ............................................................................................... 47
Added new OFFSET control bit to ID_CFG (register 00h) for ADS1283B device; no change to ADS1283 and
ADS1283A functionality........................................................................................................................................................ 48
•
Changed format of register description tables ..................................................................................................................... 48
2
版权 © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
Changes from Original (January 2014) to Revision A
Page
•
•
•
已添加 ADS1283A 器件及相关内容添加到产品说明书 ........................................................................................................... 1
Added text regarding CS high to Read Data Requirement section. .................................................................................... 44
Added text regarding CS high to SDATAC: Stop Read Data Continuous section............................................................... 45
Copyright © 2014–2019, Texas Instruments Incorporated
3
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
5 Pin Configuration and Functions
RHF Package
5-mm × 4-mm 24-Pin VQFN
Top View
DRDY
DOUT
DIN
1
2
3
4
5
6
7
19
18
17
16
15
14
13
RESET
PWDN
VREFP
VREFN
AVSS
Thermal
Pad
CS
SYNC
MFLAG
DGND
AVDD
AINN1
Not to scale
Pin Functions
PIN
I/O
DESCRIPTION
NAME
AINN1
AINN2
AINP1
AINP2
AVDD
AVSS
BYPAS
CAPN
CAPP
CLK
NO.
13
11
12
10
14
15
22
8
Analog input
Analog input
Analog input
Analog input
Analog supply
Analog supply
Analog
Negative analog input 1
Negative analog input 2
Positive analog input 1
Positive analog input 2
Positive analog power supply
Negative analog power supply
1.8-V sub-regulator output: connect 1-μF capacitor to DGND
PGA output: connect 10-nF capacitor from CAPP to CAPN
PGA output: connect 10-nF capacitor from CAPP to CAPN
Master clock input (4.096 MHz)
Analog
9
Analog
23
4
Digital input
Digital input
Ground
CS
Serial interface chip select, active low
Digital ground (tie to digital ground plane)
Digital ground (tie to digital ground plane)
Serial interface data input
DGND
DGND
DIN
7
21
3
Ground
Digital input
Digital output
Digital output
Digital supply
Digital output
Digital input
Digital input
Digital input
Digital input
Analog input
Analog input
DOUT
DRDY
DVDD
MFLAG
PWDN
RESET
SCLK
SYNC
VREFN
VREFP
2
Serial Interface data output
1
Data ready output: active low
20
6
Digital power supply: 1.65 V to 3.6 V
Modulator overrange flag: 0 = normal, 1 = modulator overrange
Power-down input, active low
18
19
24
5
Reset input, active low
Serial interface shift clock input
Synchronize input, rising edge active
Negative reference input
16
17
Positive reference input
Do not electrically connect the thermal pad. The thermal pad must be soldered to PCB.
Thermal pad vias are optional and can be removed.
Thermal pad
4
Copyright © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
6 Specifications
6.1 Absolute Maximum Ratings(1)
Over operating free-air temperature range (unless otherwise noted).
MIN
–0.3
MAX
5.5
UNIT
V
AVDD to AVSS
AVSS to DGND
–2.8
0.3
V
DVDD to DGND
–0.3
3.9
V
Analog input voltage
Digital input voltage to DGND
Input current, continuous
Operating temperature
Junction temperature
Storage temperature, Tstg
AVSS – 0.3
–0.3
AVDD + 0.3
DVDD + 0.3
10
V
V
–10
mA
°C
°C
°C
–50
125
150
–60
150
(1) Stresses above these ratings may cause permanent damage. Exposure to absolute maximum conditions for extended periods may
degrade device reliability. These are stress ratings only, and functional operation of the device at these or any other conditions beyond
those specified is not implied.
6.2 ESD Ratings
VALUE
±2000
±500
UNIT
Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1)
Charged-device model (CDM), per JEDEC specification JESD22-C101(2)
V(ESD)
Electrostatic discharge
V
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.
6.3 Recommended Operating Conditions
MIN
NOM
MAX
UNIT
POWER SUPPLY
AVSS
AVDD
DVDD
Negative analog supply (relative to DGND)
–2.6
AVSS + 4.75
1.65
0
AVSS + 5.25
3.6
V
V
V
Positive analog supply (relative to AVSS)
Digital supply (relative to DGND)
ANALOG INPUTS
FSR
Full-scale input voltage range (VIN = AINP – AINN)
±VREF / (2 × PGA)
V
Calibration margin(1)
106
%FSR
AINP or
AINN
Absolute input voltage range
AVSS + 0.7
AVDD – 1.25
V
VOLTAGE REFERENCE INPUTS
Reference input voltage (VREF = VREFP – VREFN)
Negative reference input
Positive reference input
1
AVSS – 0.1
VREFN + 1
5
(AVDD – AVSS) + 0.2
VREFP – 1
V
V
V
VREFN
VREFP
AVDD + 0.1
DIGITAL INPUTS
VIH
High-level input voltage
0.8 × DVDD
DVDD
0.2 × DVDD
4.096
V
VIL
Low-level input voltage
Clock input
DGND
1
V
fCLK
fSCLK
MHz
MHz
Serial clock rate
fCLK / 2
TEMPERATURE
Specified temperature
–40
85
°C
(1) Calibration margin is the maximum allowable input voltage after user calibration of offset and gain errors.
Copyright © 2014–2019, Texas Instruments Incorporated
5
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
6.4 Thermal Information
ADS1283
RHF (VQFN)
24 PINS
30.2
THERMAL METRIC(1)
UNIT
RθJA
Junction-to-ambient thermal resistance
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
RθJC(top)
RθJB
Junction-to-case (top) thermal resistance
Junction-to-board thermal resistance
27.5
8.5
ψJT
Junction-to-top characterization parameter
Junction-to-board characterization parameter
Junction-to-case (bottom) thermal resistance
0.3
ψJB
8.6
RθJC(bot)
1.7
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report.
6.5 Electrical Characteristics
maximum and minimum specifications over –40°C to +85°C; typical specifications at 25°C, AVDD = 2.5 V, AVSS = –2.5 V,
fCLK = 4.096 MHz, VREFP = 2.5 V, VREFN = –2.5 V, DVDD = 3.3 V, PGA = 1, OFFSET bit = 1 (enabled), CHOP bit = 1
(enabled), and fDATA = 1000 SPS (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
ANALOG INPUTS
PGA input voltage noise density
Differential input impedance(1)
5
1
nV/√Hz
GΩ
CHOP enabled
CHOP disabled
100
1
Common-mode input impedance
Input bias current
GΩ
nA
dB
Ω
IIB
1
Crosstalk
f = 31.25 Hz
Each switch
–135
30
Mux switch on-resistance
PGA OUTPUT (CAPP, CAPN)
Absolute output range
AVSS + 0.4
AVDD – 0.4
100
V
PGA differential output impedance
600
±10%
10
Ω
Output impedance tolerance
External bypass capacitance
nF
Modulator differential input impedance
55
kΩ
AC PERFORMANCE
SNR
Signal-to-noise ratio(2)
120
124
dB
dB
dB
PGA =
1, 2, 4, 8, 16
–122
–114
–110
ADS1283,
ADS1283B
Total harmonic distortion(3)
Spurious-free dynamic range
PGA = 32
–117
–114
–118
123
THD
PGA = 64
ADS1283A
PGA = 1, 4, 16
–106
SFDR
(1) PGA chop feature is disabled by setting CHOP bit = '0'. See Table 4
(2) Inputs shorted; see Table 1.
(3) Input signal = 31.25 Hz, –0.5 dBFS.
6
Copyright © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
Electrical Characteristics (continued)
maximum and minimum specifications over –40°C to +85°C; typical specifications at 25°C, AVDD = 2.5 V, AVSS = –2.5 V,
fCLK = 4.096 MHz, VREFP = 2.5 V, VREFN = –2.5 V, DVDD = 3.3 V, PGA = 1, OFFSET bit = 1 (enabled), CHOP bit = 1
(enabled), and fDATA = 1000 SPS (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
DC PERFORMANCE
Resolution
Data rate
31
250
Bits
FIR filter mode
4000
128,000
±200
fDATA
SPS
Sinc filter mode
8000
OFFSET disabled
±50
300
µV
OFFSET disabled, CHOP disabled
Offset(4)
95 / PGA
70 / PGA
100 / PGA
75 / PGA
1
105 / PGA
80 / PGA
OFFSET
enabled
mV
μV
ADS1283B only
Offset after calibration(5)
Offset drift
CHOP enabled
CHOP disabled
0.03
μV/°C
0.5
Gain error(6)
Gain error after calibration(5)
–1.5%
–1.0%
0.0002%
2
–0.5%
0.8%
PGA = 1
Gain drift
ppm/°C
PGA = 16
9
Gain matching(7)
0.3%
110
(8)
CMR
PSR
Common-mode rejection
fCM = 60 Hz, 1.25 VPP
95
80
90
dB
dB
AVDD, AVSS
90
fPS = 60 Hz, 100
Power-supply rejection
(8)
mVPP
DVDD
115
VOLTAGE REFERENCE INPUTS
Reference input impedance
DIGITAL FILTER RESPONSE
Pass-band ripple
85
kΩ
±0.003
10
dB
Hz
Hz
Hz
dB
Hz
Pass band (–0.01dB)
Bandwidth (–3dB)
0.375 × fDATA
0.413 × fDATA
High-pass filter corner
Stop band attenuation(9)
Stop band
0.1
135
0.500 × fDATA
5 / fDATA
Minimum phase filter(10)
Linear phase filter
Group delay
s
s
31 / fDATA
62 / fDATA
62 / fDATA
Minimum phase filter
Linear phase filter
Settling time (latency)
(4) Offset specification is input referred. The offset scales by the reference voltage (VREF).
(5) Calibration accuracy is on the level of noise reduced by four (calibration averages 16 readings).
(6) The PGA output impedance and the modulator input impedance results in –1% systematic gain error.
(7) Gain match relative to gain = 1.
(8) fCM is the input common-mode frequency. fPS is the power-supply frequency.
(9) Input frequencies in the range of NfCLK / 1024 ± fDATA / 2 (where N = 1, 2, 3...) can intermodulate with the modulator chopper clock (and
N multiples). At these frequencies, intermodulation = –120 dB, typ.
(10) At dc; see Figure 42.
Copyright © 2014–2019, Texas Instruments Incorporated
7
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
Electrical Characteristics (continued)
maximum and minimum specifications over –40°C to +85°C; typical specifications at 25°C, AVDD = 2.5 V, AVSS = –2.5 V,
fCLK = 4.096 MHz, VREFP = 2.5 V, VREFN = –2.5 V, DVDD = 3.3 V, PGA = 1, OFFSET bit = 1 (enabled), CHOP bit = 1
(enabled), and fDATA = 1000 SPS (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
DIGITAL INPUTS/OUTPUTS
VOH
VOL
Ilkg
High-level output voltage
Low-level output voltage
Input leakage
IOH = 1 mA
0.8 × DVDD
V
V
IOL = 1 mA
0.2 × DVDD
±10
0 < VDIGITAL IN < DVDD
μA
POWER SUPPLY
Operating PGA = 1, 2, 4, 8
Operating PGA = 16, 32, 64
Standby mode
3.2
4
5.5
6
|mA|
AVDD, AVSS current
1
15
|μA|
mA
μA
Power-down mode
Operating
1
15
0.6
25
1
0.8
50
DVDD current
Standby mode
Power-down mode(11)
Operating PGA = 1, 2, 4, 8
Operating PGA = 16, 32, 64
Standby mode
15
18
22
90
10
30
mW
33
Power dissipation
250
125
μW
Power-down mode
(11) CLK input stopped.
8
Copyright © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
6.6 Timing Requirements
at TA = –40°C to +85°C and DVDD = 1.65 V to 3.6 V (unless otherwise noted)
MIN
40
MAX
UNIT
ns
tCSSC
tSCLK
tSPWH, L
tDIST
CS low to SCLK high: setup time
SCLK period
SCLK pulse duration, high and low(1)
DIN valid to SCLK high: setup time
Valid DIN to SCLK high: hold time
CS high pulse
2
16
10
1 / fCLK
1 / fCLK
ns
0.8
50
tDIHD
50
ns
tCSH
100
24
ns
tSCCS
SCLK high to CS high
1/fCLK
(1) Holding SCLK low for 64 DRDY falling edges resets the serial interface.
6.7 Switching Characteristics
over operating free-air temperature range (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
CS low to DOUT driven: propagation
delay
tCSDOD
tDOPD
60
ns
SCLK low to valid new DOUT:
propagation delay
Load on DOUT = 20 pF || 100 kΩ
100
ns
SCLK low to DOUT invalid: hold
time
tDOHD
0
ns
ns
tCSDOZ
CS high to DOUT tristate
40
tSPWH
tSCLK
tCSH
CS
tSPWL
tCSSC
tSCCS
SCLK
tDIST
B7
DIN
B6
tDIHD
B5
B4
B3
B2
B1
B0
tDOPD
DOUT
B7
tDOHD
tCSDOD
tCSDOZ
Figure 1. Serial Interface Timing Diagram
Copyright © 2014–2019, Texas Instruments Incorporated
9
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
6.8 Typical Characteristics
At +25°C, AVDD = 2.5 V, AVSS = –2.5 V, fCLK = 4.096 MHz, VREFP = 2.5 V, VREFN = –2.5 V, DVDD = 3.3 V, PGA = 1, OFFSET enabled,
CHOP enabled, and fDATA = 1000 SPS (unless otherwise noted). For ADS1283A, the electrical characteristics apply at PGA = 1, 4, and 16
only.
0
œ20
0
œ20
8192-Point FFT
Shorted Input
PGA = 8
8192-Point FFT
Shorted Input
PGA = 1
œ40
œ40
SNR = 121.1 dB
SNR = 123.7 dB
œ60
œ60
œ80
œ80
œ100
œ120
œ140
œ160
œ180
œ100
œ120
œ140
œ160
œ180
0
0
0
50 100 150 200 250 300 350 400 450 500
0
0
0
50 100 150 200 250 300 350 400 450 500
Frequency (Hz)
Frequency (Hz)
C003
C002
Figure 3. Output Spectrum
Figure 2. Output Spectrum
0
œ20
0
œ20
8192-Point FFT
Shorted Input
PGA = 8
CHOP Disabled
SNR = 117.5 dB
8192-Point FFT
Shorted Input
PGA = 1
CHOP DIsabled
SNR = 123.5 dB
œ40
œ40
œ60
œ60
œ80
œ80
œ100
œ120
œ140
œ160
œ180
œ100
œ120
œ140
œ160
œ180
50 100 150 200 250 300 350 400 450 500
50 100 150 200 250 300 350 400 450 500
Frequency (Hz)
Frequency (Hz)
C004
C005
Figure 4. Output Spectrum
Figure 5. Output Spectrum
0
œ20
0
œ20
8192-Point FFT
V IN = 31.25 Hz, -0.5 dBFS
PGA = 1
8192-Point FFT
V IN = 31.25 Hz, -0.5 dBFS
PGA = 8
œ40
œ40
THD = -124 dB
THD = -125 dB
œ60
œ60
œ80
œ80
œ100
œ120
œ140
œ160
œ180
œ100
œ120
œ140
œ160
œ180
50 100 150 200 250 300 350 400 450 500
50 100 150 200 250 300 350 400 450 500
Frequency (Hz)
Frequency (Hz)
C002
C002
Figure 6. Output Spectrum
Figure 7. Output Spectrum
10
Copyright © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
Typical Characteristics (continued)
At +25°C, AVDD = 2.5 V, AVSS = –2.5 V, fCLK = 4.096 MHz, VREFP = 2.5 V, VREFN = –2.5 V, DVDD = 3.3 V, PGA = 1,
OFFSET enabled, CHOP enabled, and fDATA = 1000 SPS (unless otherwise noted). For ADS1283A, the electrical
characteristics apply at PGA = 1, 4, and 16 only.
0
0
8192-Point FFT
V IN = 31.25 Hz, -20 dBFS
PGA = 1
8192-Point FFT
V IN = 31.25 Hz, -20 dBFS
PGA = 8
œ20
œ20
œ40
œ40
THD = -122 dB
THD = -121 dB
œ60
œ60
œ80
œ80
œ100
œ120
œ140
œ160
œ180
œ100
œ120
œ140
œ160
œ180
0
50 100 150 200 250 300 350 400 450 500
0
50 100 150 200 250 300 350 400 450 500
Frequency (Hz)
Frequency (Hz)
C002
C002
Figure 8. Output Spectrum
Figure 9. Output Spectrum
œ100
œ105
œ110
œ115
œ120
œ125
œ130
œ100
œ105
œ110
œ115
œ120
œ125
œ130
PGA = 1
PGA = 1
VIN = 31.25 Hz, -0.5 dBFS
V IN = -0.5 dBFS
PGA = 4
PGA = 16
PGA = 64
PGA = 4
PGA = 16
PGA = 64
œ55 œ35 œ15
5
25
45
65
85
105 125
0
10 20 30 40 50 60 70 80 90 100 110 120
Temperature (°C)
Signal Frequency (Hz)
C007
C002
Figure 11. THD vs Temperature
Figure 10. THD vs Signal Frequency
140
130
120
110
100
90
140
120
100
80
PGA = 1
60
40
DVDD
AVDD
AVSS
80
20
PGA = 1
PGA = 8
70
0
10
100
1000
10000
100000
1000000
10
100
1000
10000
100000
1000000
Common Mode Frequency (Hz)
Power Supply Frequency (Hz)
C007
C007
Figure 12. CMR vs Common-Mode Frequency
Figure 13. PSR vs Power-Supply Frequency
Copyright © 2014–2019, Texas Instruments Incorporated
11
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
Typical Characteristics (continued)
At +25°C, AVDD = 2.5 V, AVSS = –2.5 V, fCLK = 4.096 MHz, VREFP = 2.5 V, VREFN = –2.5 V, DVDD = 3.3 V, PGA = 1,
OFFSET enabled, CHOP enabled, and fDATA = 1000 SPS (unless otherwise noted). For ADS1283A, the electrical
characteristics apply at PGA = 1, 4, and 16 only.
100
120
110
100
90
80
70
60
50
40
30
20
10
0
PGA = 1
PGA = 8
30 Units
OFFSET Enabled
30 units based on
20 •C intervals
over the range
-40•C to +85 •C
90
80
70
60
50
40
30
20
10
0
Offset Drift (nV/°C)
Offset (mV)
C010
C010
C010
C010
Figure 14. Offset-Voltage Histogram
Figure 15. Offset-Voltage Drift Histogram
100
90
80
70
60
50
40
30
20
10
0
150
140
130
120
110
100
90
PGA = 1,2,4
PGA = 16
30 Units
PGA = 1
30 units based on 20•C intervals
over the range -40°C to +85°•C
PGA = 8,32,64
80
70
60
50
40
30
20
10
0
Gain Drift (ppm/°C)
Gain Error (%)
C010
Figure 16. Gain-Error Histogram
Figure 17. Gain-Error Drift Histogram
125
120
115
110
105
100
95
120
110
100
90
80
70
60
50
40
30
20
10
0
Worst case gain match
30 units, relative PGA = 1
over -40 °C to +85°C range
PGA = 1
PGA = 4
PGA = 16
Shorted Input
PGA = 64
œ55 œ35 œ15
90
5
25
45
65
85
105 125
Temperature (°C)
C008
Gain Match (%)
Figure 19. SNR vs Temperature
Figure 18. Gain-Match Histogram
12
Copyright © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
Typical Characteristics (continued)
At +25°C, AVDD = 2.5 V, AVSS = –2.5 V, fCLK = 4.096 MHz, VREFP = 2.5 V, VREFN = –2.5 V, DVDD = 3.3 V, PGA = 1,
OFFSET enabled, CHOP enabled, and fDATA = 1000 SPS (unless otherwise noted). For ADS1283A, the electrical
characteristics apply at PGA = 1, 4, and 16 only.
0
25
20
15
10
5
8192-Point FFT (IN1)
IN1: Shorted
IN2: 31.25 Hz, -0.5 dBFS
PGA = 8
œ20
œ40
œ60
œ80
œ100
œ120
œ140
œ160
œ180
PGA = 1,2,4,8
PGA = 16,32,64
0
0
50 100 150 200 250 300 350 400 450 500
œ55 œ35 œ15
5
25
45
65
85
105 125
Frequency (Hz)
C005
Temperature (°C)
C009
Figure 20. Crosstalk Output Spectrum
Figure 21. Power vs Temperature
2.0
1.5
2.0
1.5
P Input, T = 25°C
P Input, T = 25°C
CHOP Enabled
PGA = 1
CHOP Disabled
PGA = 1
N Input, T = 25°C
P Input, T = 85°C
N Input, T = 85°C
N Input, T = 25°C
P Input, T = 85°C
N Input, T = 85°C
1.0
1.0
0.5
0.5
0.0
0.0
œ0.5
œ1.0
œ1.5
œ2.0
œ0.5
œ1.0
œ1.5
œ2.0
œ2.5 œ2.0 œ1.5 œ1.0 œ0.5 0.0 0.5 1.0 1.5 2.0 2.5
œ2.5 œ2.0 œ1.5 œ1.0 œ0.5 0.0 0.5 1.0 1.5 2.0 2.5
Differential Input Voltage (V)
Differential Input Voltage (V)
C002
C002
Figure 22. Input Bias Current vs Input Voltage
Figure 23. Input Bias Current vs Input Voltage
86
84
82
80
78
76
œ55 œ35 œ15
5
25
45
65
85
105 125
Temperature (°C)
C002
Figure 24. Reference Input Impedance vs Temperature
Copyright © 2014–2019, Texas Instruments Incorporated
13
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
7 Parameter Measurement Information
7.1 Noise Performance
The ADS1283 offers outstanding signal-to-noise ratio (SNR). The SNR depends on the ADC data rate and the
PGA gain selected. As the bandwidth is reduced by decreasing the data rate, the SNR improves
correspondingly. Similarly, as gain is increased, the input-referred noise decreases. The PGA noise is
independent of gain; therefore, as the gain increases, the input range correspondingly decreases, resulting in
decreased SNR.
The ADS1283 provides a chop feature that reduces the PGA 1/f noise. See the Programmable Gain Amplifier
(PGA) section for more information about chopping. Table 1 summarizes the SNR and input noise voltage with
the CHOP bit enabled. Disabling the CHOP bit results in increased low-frequency noise, particularly evident with
high PGA gains and lower sample rates. Table 2 summarizes SNR and input noise voltage with CHOP disabled.
Table 1. Signal-to-Noise Ratio (dB) and Input Noise (µV), CHOP Bit Enabled
PGA (SNR, dB)(1)
PGA (Input-Referred Noise, µV RMS)
DATA RATE
(SPS)
1
2
4
8
16
32
64
1
2
4
8
16
32
64
250
500
130
127
124
121
117
129
126
123
120
117
129
126
123
120
117
127
124
121
118
115
125
122
119
116
113
119
116
113
110
107
114
111
108
105
102
0.59
0.84
1.19
1.68
2.40
0.30
0.43
0.60
0.86
1.22
0.16
0.23
0.32
0.46
0.66
0.10
0.14
0.20
0.28
0.40
0.07
0.09
0.13
0.18
0.26
0.06
0.09
0.12
0.17
0.25
0.06
0.08
0.11
0.16
0.23
1000
2000
4000
(1) Typical values at T = +25°C and VREF = 5 V. SNR values rounded to the nearest dB. Number of ADC conversions used in the analysis
varied to maintain measurement bandwidth = 0.1 Hz to 0.413 × data rate. Note that SNR and input noise data of ADS1283A applies to
PGA = 1, 4, and 16 only.
Table 2. Signal-to-Noise Ratio (dB) and Input Noise (µV), CHOP Bit Disabled
PGA (SNR, dB)(1)
PGA (Input-Referred Noise, µV RMS)
DATA RATE
(SPS)
1
2
4
8
16
32
64
1
2
4
8
16
32
64
250
500
129
126
123
120
117
128
125
123
120
117
125
123
121
119
116
120
119
117
116
114
116
114
114
112
111
110
108
108
107
105
104
103
102
101
99
0.63
0.87
1.20
1.69
2.41
0.37
0.47
0.65
0.91
1.24
0.26
0.31
0.39
0.51
0.70
0.21
0.25
0.30
0.37
0.46
0.18
0.21
0.22
0.26
0.33
0.17
0.21
0.22
0.25
0.31
0.18
0.20
0.22
0.25
0.30
1000
2000
4000
(1) Typical values at T = +25°C and VREF = 5 V. SNR values rounded to the nearest dB. Number of ADC conversions used in the analysis
varied to maintain measurement bandwidth = 0.1 Hz to 0.413 × data rate. Note that SNR and input noise data of ADS1283A applies to
PGA = 1, 4, and 16 only.
Input-referred noise is related to SNR by Equation 1:
FSRRMS
SNR = 20log
NRMS
where
•
•
FSRRMS = Full-scale range RMS = VREF / (2 × √2 × PGA)
NRMS = Noise (RMS, input-referred)
(1)
14
Copyright © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
8 Detailed Description
8.1 Overview
The ADS1283 is a high-performance analog-to-digital converter (ADC) intended for energy exploration, seismic
monitoring, chromatography, and other exacting performance applications. The converter provides 31-bit
resolution in data rates from 250 SPS to 4000 SPS. See the Functional Block Diagram section for a block
diagram of the ADS1283.
The ADS1283A device is functionally equivalent to the ADS1283, except that the ADS1283A supports PGA
gains of 1, 4, and 16 only. The ADS1283A also relaxes the THD specification of these gains. See the Electrical
Characteristics section for more details. The ADS1283B provides equivalent performance to the ADS1283, but
provides two offset voltage options, 75 mV and 100 mV. See Offset for details.
The two-channel input mux allows five configurations:
1. Input 1
2. Input 2
3. Input 1 and input 2 shorted together
4. Input 1 and input 2 disconnected and PGA input internally shorted with two 400-Ω resistors
5. Input 1 and input 2 shorted to perform input common-mode test
See the Analog Inputs and Multiplexer section for more details.
The input mux is followed by a continuous-time PGA, featuring very low noise of 5 nV/√Hz. The PGA is
controlled by register settings, allowing gains from 1 to 64 for the ADS1283 and ADS1283B, and gains of 1, 4,
and 16 for the ADS1283A.
The inherently-stable, fourth-order, delta-sigma modulator measures the differential input signal
(VIN = AINP – AINN) against the differential reference (VREF = VREFP – VREFN). A digital output (MFLAG)
indicates that the modulator is in overload as a result of an overdrive condition. The modulator connects to the
on-chip digital filter that provides the output codes.
The digital filter consists of a variable decimation rate, fifth-order sinc filter, followed by a variable phase,
decimate-by-32, finite-impulse response (FIR) low-pass filter with programmable phase, and then by an
adjustable high-pass filter for dc removal of the output code. The output of the digital filter can be taken from the
sinc or the FIR low-pass, with the FIR option of the infinite impulse response (IIR) high-pass section.
Gain and offset registers scale the digital filter output to produce the final code value. The scaling feature can be
used for calibration and sensor gain matching.
The SYNC input resets the operation of both the digital filter and the modulator, allowing synchronization
conversions of multiple ADS1283 devices to an external event. The SYNC input supports a continuously-toggled
input mode that accepts an external data frame clock locked to the conversion rate.
The RESET input resets the register settings and also restarts the conversion process.
The PWDN input sets the device into a micro-power state. Note that register settings are not retained in PWDN
mode. Use the STANDBY command in its place if it is desired to retain register settings (the quiescent current in
standby mode is slightly higher).
Noise-immune Schmitt-trigger and clock-qualified inputs (RESET and SYNC) provide increased reliability in high-
noise environments. The SPI™-compatible serial interface is used to read conversion data, in addition to reading
from and writing to the configuration registers.
The device allows either unipolar and bipolar analog power-supply operation. The analog supplies may be set to
+5 V for unipolar signals (with the inputs level shifted externally), or set to ±2.5 V to accept true bipolar input
signals (ground referenced). The digital supply is separate and accepts voltages from 1.8 V to 3.3 V,
independent of the analog power supplies used.
An internal subregulator is used to supply the digital core from DVDD. BYPAS (pin 28), is the subregulator output
and requires a 1-μF capacitor for noise reduction. Note that the regulated output voltage on BYPAS is not
available to drive external circuitry.
Copyright © 2014–2019, Texas Instruments Incorporated
15
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
8.2 Functional Block Diagram
AVDD
BYPAS DVDD
CLK
+1.8 V
(Digital core)
LDO
AINP2
AINN2
AINP1
AINN1
300
300
W
W
CS
4th-Order
ûꢀ
Modulator
SCLK
DIN
Programmable
Digital Filter
Serial
PGA
Calibration
Interface
DOUT
Overrange
Detection
DRDY
SYNC
400 Ω
400 Ω
Control
RESET
PWDN
AVDD + AVSS
2
AVSS
MFLAG
DGND
8.3 Feature Description
8.3.1 Analog Inputs and Multiplexer
A diagram of the input multiplexer is shown in Figure 25.
AVDD
S1
S2
AINP1
ESD Diodes
AINP2
(+)
400W
S3
S7
AVSS
To PGA
AVDD + AVSS
AVDD
2
400W
S4
S5
S6
AINN1
AINN2
(-)
ESD Diodes
AVSS
Figure 25. Analog Inputs and Multiplexer
ESD diodes protect the multiplexer inputs. If either input is taken below AVSS – 0.3 V, or above AVDD + 0.3 V,
the ESD protection diodes can turn on. If these conditions are possible, use external clamp diodes, series
resistors, or both to limit the input current to safe values (see the Absolute Maximum Ratings table).
16
Copyright © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
Feature Description (continued)
Also, overdriving one unused input can affect the conversions of the other input. If an overdriven input interacts
with the measured input, clamp the overdriven signal with external Schottky diodes.
The specified input operating range of the PGA is shown in Equation 2:
AVSS + 0.7V < (AINN or AINP) < AVDD - 1.25V
(2)
For best operation, maintain absolute input levels (input signal level and common-mode level) within these limits.
The multiplexer connects one of the two external differential inputs to the preamplifier inputs, in addition to
internal connections for various self-test modes. Table 3 summarizes the multiplexer configurations for Figure 25.
Table 3. Multiplexer Modes
MUX[2:0]
000
SWITCHES
S1, S5
DESCRIPTION
AINP1 and AINN1 connected to preamplifier
001
S2, S6
AINP2 and AINN2 connected to preamplifier
010
S3, S4
Preamplifier inputs shorted together through 400-Ω internal resistors
AINP1, AINN1 and AINP2, AINN2 connected together and to the preamplifier
External short, preamplifier inputs shorted to AINN2 (common-mode test)
011
S1, S5, S2, S6
S6, S7
100
The typical on-resistance (RON) of the multiplexer is 30 Ω (each switch). When the multiplexer is used to drive an
external load on one input by a signal generator on the other input, on-resistance and on-resistance amplitude
dependency can lead to measurement errors. Figure 26 shows THD versus load resistance and amplitude. THD
improves with high-impedance loads and with lower-amplitude drive signals. The data are measured with the
circuit from Figure 27 with MUX[2:0] = 011.
0
PGA = 1
PGA = 2
PGA = 4
PGA = 8
-20
-40
PGA = 16
PGA = 32
PGA = 64
-60
-80
-100
-120
-140
0.1k
1k
10k
100k
1M
10M
RLOAD (W)
Figure 26. THD vs External Load and Signal Magnitude (PGA); See Figure 27
500 Ω
Input 1
Test Signal
500 W
Input 2
RLOAD
Figure 27. Driving an External Load Through the Multiplexer
Copyright © 2014–2019, Texas Instruments Incorporated
17
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
8.3.2 Programmable Gain Amplifier (PGA)
The PGA of the ADS1283 is a low-noise, continuous-time, differential-in and differential-out CMOS amplifier. The
gain is set by register bits PGA[2:0], and is programmable from 1 to 64 for the ADS1283, or can be set to 1, 4,
and 16 for the ADS1283A. The PGA differentially drives the modulator through 300-Ω internal resistors. A C0G
capacitor (10-nF C0G or film dielectric) must be connected to CAPP and CAPN to filter modulator sampling
glitches. The external capacitor also serves as an antialias filter. The corner frequency is given in Equation 3:
1
fP =
6.3 ´ 600 ´ C
(3)
The ADS1283 PGA provides a chop feature. As shown in Figure 28, amplifiers A1 and A2 are chopper stabilized
to remove the offset, offset drift, and 1/f noise. Chopper stabilization (or chopping) moves the offset and noise to
fCLK / 1024 (4 kHz, fCLK = 4.096 MHz ), which is located safely out of the pass-band frequency. Chopping can be
disabled by setting the CHOP bit = 0. When chopping is disabled, the PGA input impedance increases (see
Differential Input Impedance parameter in the Electrical Characteristics). As shown in Figure 29, chopping
maintains flat noise density, leaving predominantly white noise. However, if chopping is disabled, the PGA input
noise results in a rising 1/f noise profile.
AVDD
MUX (+)
300W
A1
CAPP
CHOP
Gain Control
10nF
PGA[2:0] Bits
(55kW, typ
Modulator
Effective
Impedance
)
CAPN
300W
A2
MUX (-)
Chopping Control CHOP Bit
AVSS
(1) Modulator input impedance scales with clock rate.
Figure 28. PGA Block Diagram
100
PGA CHOP Off
PGA CHOP On
10
1
1
10
100
Frequency (Hz)
1k
Figure 29. PGA Noise
18
Copyright © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
As a result of the stray capacitance of the input chopping switches, low-level transient currents flow through the
inputs when chopping is enabled. The average value of the transient currents versus the input voltage results in
an effective input impedance. The effective input impedance depends on the PGA gain, as shown in Table 4.
Despite the relatively high input impedance, carefully evaluate applications with high-impedance sensors or high-
impedance termination resistors when chopping is enabled. Table 4 shows the PGA differential input impedance
with CHOP enabled.
Table 4. Differential Input Impedance (CHOP Enabled)
PGA
1
DIFFERENTIAL INPUT IMPEDANCE (GΩ)
7
7
2
4
4
8
3
16
32
64
2
1
0.5
The PGA has programmable gains from 1 to 64. Table 5 shows the register bit setting for the PGA and resulting
full-scale differential range.
Table 5. PGA Gain Settings
DIFFERENTIAL INPUT RANGE
PGA[2:0]
000
GAIN(1)
(V)(2)
±2.5
1
2
001
±1.25
010
4
±0.625
±0.312
±0.156
±0.078
±0.039
011
8
100
16
32
64
101
110
(1) The ADS1283A supports gains of 1, 4, and 16 only.
(2) VREF = 5 V. The input range scales with VREF
.
The specified range of the PGA output is shown in Equation 4:
AVSS + 0.4V < (CAPN or CAPP) < AVDD - 0.4V
(4)
For best performance, maintain PGA output levels (signal + common-mode) within these limits.
Copyright © 2014–2019, Texas Instruments Incorporated
19
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
8.3.3 Analog-to-Digital Converter (ADC)
The ADC block of the ADS1283 is composed of two sections: a high-accuracy modulator and a programmable
digital filter.
8.3.3.1 Modulator
The high-performance modulator is an inherently-stable, fourth-order, ΔΣ, 2 + 2 pipelined structure, as Figure 30
shows. The modulator shifts the quantization noise to a higher frequency (out of the pass band), where the noise
can be easily removed by digital filtering. The modulator data can either be completely filtered by the on-chip
digital filter or partially filtered by the onboard sinc filter in conjunction with external, post-processing filters.
fCLK/4
fMOD =
1st-Stage
(2nd-Order ûꢀ)
Analog
Signal
Digital
Filter
Math
Block
2nd-Stage
(2nd-Order
ûꢀ)
Figure 30. Fourth-Order Modulator
The modulator performance is optimized for input signals over the dc to 2-kHz bandwidth. As Figure 31 shows,
the effect of PGA and modulator chop result in spectral artifacts at the chop frequency (4 kHz) and related odd-
order harmonics to the chop frequency. When using the sinc filter mode in conjunction with an external post-
decimation filter, design the external digital filter to suppress the modulator chopping artifacts.
0
œ20
œ40
œ60
œ80
œ100
œ120
œ140
œ160
œ180
0
4000 8000 12000 16000 20000 24000 28000 32000
Frequency (Hz)
C001
Figure 31. Sinc Output FFT (64 kSPS)
8.3.3.1.1 Modulator Overrange
The ADS1283 modulator is inherently stable, and therefore, has predictable recovery behavior resulting from an
input overdrive condition. The modulator does not exhibit self-reset cycles, which often results in an unstable
output data stream. The ADS1283 modulator outputs a data stream with 90% duty cycle of ones-to-zeroes
density with the positive full-scale input signal applied (10% duty cycle with the negative full-scale signal). If the
input is overdriven past 90% modulation, but below 100% modulation (10% and 0% for negative overdrive,
respectively), the modulator remains stable and continues to output the 1s density data stream. The digital filter
may or may not clip the output codes to +FS or –FS, depending on the duration of the overdrive. When the input
returns to the normal range from a long-duration overdrive (worst case), the modulator returns immediately to the
normal range, but the group delay of the digital filter delays the return of the conversion result to within the linear
range (31 readings for linear phase FIR). An additional 31 readings (62 total) are required for completely-settled
data.
20
Copyright © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
If the inputs are sufficiently overdriven to drive the modulator to full duty cycle (that is, all 1s or all 0s), the
modulator enters a stable saturated state. The digital output code may clip to +FS or –FS, again depending on
the duration. A small-duration overdrive condition may not always clip the output code. When the input returns to
the normal range, the modulator requires up to 12 modulator clock cycles (fMOD) to exit saturation and return to
the linear region. The digital filter requires an additional 62 conversions for fully-settled data (linear-phase FIR).
In the extreme case of input overrange (where either overdriven input exceeds the voltage of the analog supply
voltage plus an internal ESD diode drop), the internal diodes begin to conduct, thus clipping the input signal.
When the input overdrive is removed, the diodes recover quickly. Make sure to limit the input current to 10 mA
(continuous duty) if an overvoltage condition is possible.
8.3.3.1.2 Modulator Input Impedance
The modulator samples the buffered input voltage with an internal capacitor to perform conversions. The
charging of the input sampling capacitor draws a transient current from the PGA output. Use the average value
of the current to calculate an effective input impedance, as shown in Equation 5:
REFF = 1 / (fMOD × CS)
where
•
•
fMOD = Modulator sample frequency = CLK / 4
CS = Input sampling capacitor = 17 pF (typ)
(5)
The resulting modulator input impedance is 55 kΩ (CLK = 4.096 MHz). The modulator input impedance and the
internal PGA 300-Ω output resistors result in a systematic gain error of –1%. The modulator CS can vary ±20%
over production lots, affecting the nominal gain error.
8.3.3.1.3 Modulator Overrange Detection (MFLAG)
The ADS1283 has a fast-responding, overrange detection that indicates when the differential input exceeds
100% or –100% full-scale. The threshold tolerance is ±2.5%.The MFLAG output pin asserts high when in an
overrange condition. As Figure 32 and Figure 33 illustrate, the absolute differential input is compared to 100% of
range. The output of the comparator is sampled at the rate of fMOD / 2, yielding the MFLAG output. The minimum
detectable MFLAG pulse duration is fMOD / 2.
AINP
å
IABSI
P
100% FS
AINN
Q
MFLAG
Pin
fMOD/2
Figure 32. Modulator Overrange Block Diagram
+100
(AINP - AINN)
0
Time
-100
MFLAG
Pin
Figure 33. Modulator Overrange Flag Operation
Copyright © 2014–2019, Texas Instruments Incorporated
21
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
8.3.3.1.4 Offset
The ADC modulator can produce low-level idle tones that appear in the spectrum when there is no signal input or
when low-level signal inputs are present to the ADC. The ADC provides an optional dc offset voltage designed to
shift the idle tones to the stop band of digital filter response, where the idle tones are reduced. The internal offset
is applied to the modulator input; therefore, the offset voltage amplitude is independent of PGA gain. For all
ADS1283 versions, the offset option is 100 mV. For the ADS1283B, a second offset option is 75 mV. The 75-mV
offset optimally reduces idle tones under various gain, data rate, and chop mode settings.
The offset is enabled by the OFFSET1 and OFFSET0 bits (default is off). The offset voltage reduces the
available input range 4% (3% for the 75 mV value) before the onset of clipped codes. The offset voltage can be
calibrated by using the offset calibration register (OFC[2:0]). Use the offset calibration register to compensate the
offset voltage, thereby restoring the full input voltage range. See Offset and Full-Scale Calibration Registers and
Calibration Commands (OFSCAL and GANCAL) sections for more details.
8.3.3.1.5 Voltage Reference Inputs (VREFP, VREFN)
The voltage reference for the ADS1283 is the differential voltage between VREFP and VREFN:
VREF = VREFP – VREFN
(6)
The reference inputs use a structure similar to that of the analog inputs with the circuitry of the reference inputs
shown in Figure 34. The average load presented by the switched-capacitor reference input can be modeled with
an effective differential impedance of:
REFF = tSAMPLE / CIN (tSAMPLE = 1 / fMOD).
(7)
Note that the effective impedance of the reference inputs loads the external reference.
AVDD
fMOD = fCLK/4
ESD
Diodes
1
REFF
=
f
MOD x 11.5 pF
VREFP
VREFN
REFF : 85 kΩ
11.5pF
ESD
Diodes
AVSS
Figure 34. Simplified Reference Input Circuit
Place a 0.1-µF ceramic capacitor directly between the ADC VREFP and VREFN pins. Multiple ADC applications
can share a single voltage reference, but must have individual capacitors placed for each ADC.
The ADS1283 reference inputs are protected by ESD diodes. In order to prevent these diodes from turning on,
the voltage on either input must stay within the range shown in Equation 8:
AVSS - 300mV < (VREFP or VREFN) < AVDD + 300mV
(8)
The minimum valid input for VREFN is AVSS – 0.1 V, and the maximum valid input for VREFP is AVDD + 0.1 V.
To achieve the best performance from the ADS1283, use a high-quality 5-V reference voltage. A 4-V or 4.5-V
reference voltage can be used; however, this lower reference voltage reduces the signal input range with a
corresponding decrease of SNR. Noise and drift on the reference degrade overall system performance. To
achieve optimum performance, make sure to give special care to the circuitry generating the reference voltages.
See the Application Information section for reference recommendations.
22
Copyright © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
8.3.3.2 Digital Filter
The digital filter receives the modulator output and decimates the data stream. By adjusting the amount of
filtering, tradeoffs can be made between resolution and data rate: filter more for higher resolution, filter less for
higher data rate.
The digital filter is comprised of three cascaded filter stages: a variable-decimation, fifth-order sinc filter; a fixed-
decimation FIR, low-pass filter (LPF) with selectable phase; and a programmable, first-order, high-pass filter
(HPF), as shown in Figure 35.
Filter Mode
(Register Select)
Filter
MUX
To Output Register
Sinc Filter
(Decimate by
8 to 128)
Coefficient Filter
(FIR)
(Decimate by 32)
High-Pass Filter
(IIR)
Code
Clip
CAL
Block
From Modulator
Figure 35. Digital Filter and Output Code Processing
The output can be taken from one of the three filter blocks, as Figure 35 shows. For partial filtering by the
ADS1283, select the sinc filter output. For complete on-chip filtering, activate both the sinc + FIR stages. The
HPF can then be included to remove dc and low frequencies from the data. Table 6 shows the filter options.
Table 6. Digital Filter Selection
FILTR[1:0] BITS
DIGITAL FILTERS SELECTED
Reserved (not used)
Sinc
00
01
10
Sinc + FIR
Sinc + FIR + HPF
(low-pass and high-pass)
11
Copyright © 2014–2019, Texas Instruments Incorporated
23
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
8.3.3.2.1 Sinc Filter Stage (sinx / x)
The sinc filter is a variable decimation rate, fifth-order, low-pass filter. Data are supplied to this section of the filter
from the modulator at the rate of fMOD (fCLK / 4). The sinc filter attenuates the high-frequency noise of the
modulator, then decimates the data stream into parallel data. The decimation rate affects the overall data rate of
the converter, and is set by the DR[2:0] register bits, as shown in Table 7.
Table 7. Sinc Filter Data Rates
DR[2:0] REGISTER
DECIMATION RATIO (N)
DATA RATE (SPS)
8,000
000
001
010
011
100
128
64
32
16
8
16,000
32,000
64,000
128,000
Equation 9 shows the scaled Z-domain transfer function of the sinc filter.
5
-N
1 - Z
-1
N(1 - Z )
H(Z) =
where
•
N = decimation ratio
(9)
Equation 10 shows the frequency domain transfer function of the sinc filter.
5
pN ´ f
sin
fMOD
½H(f)½ =
p ´ f
N sin
fMOD
where
•
N = decimation ratio (see Table 7)
(10)
The sinc filter has notches (or zeros) that occur at the output data rate and multiples thereof. At these
frequencies, the filter has zero gain. Figure 36 shows the frequency response of the sinc filter and Figure 37
shows the roll-off of the sinc filter.
0
-20
0
-0.5
-1.0
-1.5
-2.0
-2.5
-3.0
-40
-60
-80
-100
-120
-140
0
1
2
3
4
5
0
0.05
0.10
0.15
0.20
Normalized Frequency (fIN/fDATA
)
Normalized Frequency (fIN/fDATA
)
Figure 36. Sinc Filter Frequency Response
(N = 32)
Figure 37. Sinc Filter Roll-Off
24
Copyright © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
8.3.3.2.2 FIR Stage
The second stage of the ADS1283 digital filter is an FIR low-pass filter. Data are supplied to this stage from the
sinc filter. The FIR stage is segmented into four substages, as shown in Figure 38.
FIR Stage 1
Decimate by 2
FIR Stage 2
Decimate by 2
FIR Stage 3
Decimate by 4
FIR Stage 4
Decimate by 2
Sinc
Filter
Output
Coefficients
Linear
Minimum
PHASE Select
Figure 38. FIR Filter Substages
The first two substages are half-band filters with decimation ratios of two. The third substage decimates by four,
and the fourth substage decimates by two. The overall decimation of the FIR stage is 32. Note that two
coefficient sets are used for the third and fourth sections, depending on the phase selection. Table 8 lists the
data rates and overall decimation ratio of the FIR stage. See Table 9 for the FIR filter coefficients.
Table 8. FIR Filter Data Rates
DR[2:0] REGISTER
DECIMATION RATIO (N)
FIR DATA RATE (SPS)
000
001
010
011
100
4096
2048
1024
512
250
500
1000
2000
4000
256
Table 9. FIR Stage Coefficients
SECTION 1
SECTION 2
SECTION 3
SECTION 4
SCALING = 1 / 134217728
SCALING = 1 / 134217728
LINEAR PHASE
SCALING =
1 / 512
LINEAR PHASE
SCALING =
1 / 8388608
LINEAR
PHASE
MINIMUM
PHASE
LINEAR
PHASE
MINIMUM
PHASE
COEFFICIENT
b0
b1
3
0
–10944
0
0
819
–132
–432
11767
0
8211
133882
b2
–25
0
103807
0
–73
44880
–75
769961
b3
–874
174712
2481
2940447
b4
150
256
150
0
–507903
0
–4648
536821
6692
8262605
b5
–16147
–41280
–80934
–120064
–118690
–18203
224751
580196
893263
891396
293598
–987253
–2635779
–3860322
–3572512
1372637
3012996
5788605
9852286
14957445
20301435
24569234
26260385
24247577
18356231
9668991
327749
7419
17902757
30428735
40215494
39260213
23325925
–1757787
–21028126
–21293602
–3886901
14396783
16314388
1518875
b6
2512192
4194304
2512192
0
–266
b7
–10663
–8280
10620
22008
348
b8
–25
0
b9
b10
b11
b12
b13
b14
b15
b16
b17
b18
b19
3
–507903
0
103807
0
–34123
–25549
33460
61387
–7546
–94192
–50629
101135
–10944
–7171917
–10926627
–10379094
–12979500
–11506007
2769794
Copyright © 2014–2019, Texas Instruments Incorporated
25
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
Table 9. FIR Stage Coefficients (continued)
SECTION 1
SECTION 2
SECTION 3
SECTION 4
SCALING = 1 / 134217728
SCALING = 1 / 134217728
LINEAR PHASE
SCALING =
1 / 512
LINEAR PHASE
SCALING =
1 / 8388608
LINEAR
PHASE
MINIMUM
PHASE
LINEAR
PHASE
MINIMUM
PHASE
COEFFICIENT
b20
b21
b22
b23
b24
b25
b26
b27
b28
b29
b30
b31
b32
b33
b34
b35
b36
b37
b38
b39
b40
b41
b42
b43
b44
b45
b46
b47
b48
b49
b50
b51
b52
b53
b54
b55
b56
b57
b58
b59
b60
b61
b62
b63
b64
–822573
4669054
12153698
19911100
25779390
27966862
25779390
19911100
12153698
4669054
–822573
–3572512
–3860322
–2635779
–987253
293598
891396
893263
580196
224751
–18203
–118690
–120064
–80934
–41280
–16147
–4648
–6505618
–1333678
2972773
5006366
4566808
2505652
126331
–1496514
–1933830
–1410695
–502731
245330
565174
492084
231656
–9196
134826
–56626
12195551
6103823
–6709466
–9882714
–353347
8629331
5597927
–4389168
–7594158
–428064
6566217
4024593
–3679749
–5572954
332589
–220104
–56082
263758
231231
–215231
–430178
34715
580424
283878
–588382
–693209
366118
1084786
132893
5136333
2351253
–3357202
–3767666
1087392
3847821
919792
–125456
–122207
–61813
–4445
–1300087
–878642
1162189
1741565
–522533
–2490395
–688945
2811738
2425494
–2338095
–4511116
641555
22484
22245
10775
–2918303
–2193542
1493873
2595051
–79991
940
–2953
–2599
–1052
–874
–43
–2260106
–963855
1482337
1480417
–586408
–1497356
–168417
1166800
644405
–73
214
6661730
2950811
–8538057
–10537298
9818477
41426374
56835776
41426374
9818477
–10537298
–8538057
2950811
6661730
641555
0
132
0
33
0
0
–675082
–806095
211391
740896
141976
–527673
–327618
278227
–4511116
–2338095
2425494
363809
26
Copyright © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
Table 9. FIR Stage Coefficients (continued)
SECTION 1
SECTION 2
SECTION 3
SECTION 4
SCALING = 1 / 134217728
SCALING = 1 / 134217728
LINEAR PHASE
SCALING =
1 / 512
LINEAR PHASE
SCALING =
1 / 8388608
LINEAR
PHASE
MINIMUM
PHASE
LINEAR
PHASE
MINIMUM
PHASE
COEFFICIENT
b65
2811738
–688945
–2490395
–522533
1741565
1162189
–878642
–1300087
132893
1084786
366118
–693209
–588382
283878
580424
34715
–70646
–304819
–63159
205798
124363
–107173
–131357
31104
107182
15644
–71728
–36319
38331
38783
–13557
–31453
–1230
20983
7729
–11463
–8791
4659
7126
–732
–4687
–976
2551
1339
–1103
–1085
314
b66
b67
b68
b69
b70
b71
b72
b73
b74
b75
b76
b77
b78
b79
b80
b81
–430178
–215231
231231
263758
–56082
–220104
–56626
134826
101135
–50629
–94192
–7546
b82
b83
b84
b85
b86
b87
b88
b89
b90
b91
b92
b93
61387
b94
33460
b95
–25549
–34123
348
b96
681
b97
16
b98
22008
–349
–96
b99
10620
b100
b101
b102
b103
b104
b105
b106
b107
b108
b109
–8280
144
–10663
–266
78
–46
7419
–42
6692
9
2481
16
–75
0
–432
–4
–132
0
0
0
Copyright © 2014–2019, Texas Instruments Incorporated
27
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
As shown in Figure 39, the FIR frequency response provides a flat pass band to 0.375 of the data rate
(±0.003 dB pass-band ripple). Figure 40 shows the transition from pass band to stop band.
2.0
1.5
20
0
-20
1.0
-40
0.5
-60
0
-80
-0.5
-1.0
-1.5
-2.0
-100
-120
-140
-160
0
0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40
Normalized Input Frequency (fIN/fDATA
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Normalized Input Frequency (fIN/fDATA
)
)
Figure 40. FIR Transition Band Magnitude Response
Figure 39. FIR Pass-Band Magnitude Response (fDATA
500 Hz)
=
Although not shown in Figure 40, the pass-band response repeats at multiples of the modulator frequency
(NfMOD – f0 and NfMOD + f0, where N = 1, 2, and so on, and f0 = pass band). These image frequencies, if present
in the signal and not externally filtered, fold back (or alias) into the pass band and cause errors. A low-pass
signal filter reduces the effect of aliasing. Often, the RC low-pass filter provided by the PGA output resistors and
the external capacitor connected to CAPP and CAPN provide sufficient signal attenuation.
8.3.3.2.3 Group Delay and Step Response
The FIR block is implemented as a multistage FIR structure with selectable linear or minimum phase response.
The pass band, transition band, and stop band responses of the filters are nearly identical but differ in the
respective phase responses.
8.3.3.2.3.1 Linear Phase Response
Linear phase filters exhibit constant delay time versus input frequency (that is, constant group delay). Linear
phase filters have the property that the time delay is constant from any instant of the input signal to the same
instant of the output data, and is independent of the signal nature. This filter behavior results in essentially zero
phase error when analyzing multitone signals. However, the group delay and settling time of the linear phase
filter are somewhat larger than the minimum phase filter, as shown in Figure 41.
1.4
Minimum Phase Filter
1.2
1.0
0.8
0.6
0.4
0.2
Linear Phase Filter
0
-0.2
0
5
10 15 20 25 30 35 40 45 50 55 60 65
Time Index (1/fDATA
)
Figure 41. FIR Step Response
28
Copyright © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
8.3.3.2.3.2 Minimum Phase Response
The minimum phase filter provides a short delay from the arrival of an input signal to the output, but the
relationship (phase) is not constant versus frequency, as shown in Figure 42. The filter phase is selected by the
PHS bit, as Table 10 shows.
35
Linear Phase Filter
30
25
20
15
10
Minimum Phase Filter
5
0
20
40
60
80 100 120 140 160 180 200
Frequency (Hz)
Figure 42. FIR Group Delay (fDATA = 500Hz)
Table 10. FIR Phase Selection
PHS BIT
FILTER PHASE
Linear
0
1
Minimum
Copyright © 2014–2019, Texas Instruments Incorporated
29
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
8.3.3.2.4 HPF Stage
The last stage of the ADS1283 filter block is a first-order HPF implemented as an IIR structure. This filter stage
blocks dc signals, and rolls off low-frequency components below the cutoff frequency. The transfer function for
the filter is shown in Equation 11:
-1
2 - a
1 - Z
HPF(Z) =
´
-1
2
1 - bZ
where
•
b is calculated as shown in Equation 12
(11)
(12)
1 + (1 - a)2
b =
2
The high-pass corner frequency is programmed by registers HPF[1:0], in hexadecimal. Equation 13 is used to set
the high-pass corner frequency. Table 11 lists example values for the high-pass filter.
cos wN + sin wN - 1
HPF[1:0] = 65,536 1 -
1 - 2
cos wN
where
•
•
•
•
HPF = High-pass filter register value (converted to hexadecimal)
ωN = 2πfHP / fDATA (normalized frequency, radians)
fHP = High-pass corner frequency (Hz)
fDATA = Data rate (Hz)
(13)
Table 11. High-Pass Filter Value Examples
fHP (Hz)
0.5
DATA RATE (SPS)
HPF[1:0]
0337h
250
500
1.0
0337h
1.0
1000
019Ah
30
Copyright © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
The HPF causes a small gain error, in which case the magnitude of the error depends on the ratio of fHP / fDATA
.
For many common values of (fHP / fDATA), the gain error is negligible. Figure 43 shows the gain error of the HPF.
0
-0.10
-0.20
-0.30
-0.40
-0.50
0.0001
0.001
0.01
0.1
Frequency Ratio (fHP/fDATA
)
Figure 43. HPF Gain Error
The gain error factor is illustrated in Equation 14:
cos wN + sin wN - 1
1 +
1 - 2
cos wN
HPF Gain =
cos wN + sin wN - 1
cos wN
2 -
(14)
Figure 44 shows the first-order amplitude and phase response of the HPF. In the case of applying step inputs or
synchronizing, make sure to take the settling time of the filter into account.
0
90
75
60
45
30
-7.5
-15.0
-22.5
-30.0
-37.5
-45.0
Amplitude
Phase
15
0
0.01
0.1
1
10
100
Normalized Frequency (f/fC)
Figure 44. HPF Amplitude and Phase Response
8.3.4 Master Clock Input (CLK)
The ADS1283 requires a clock for operation. The nominal clock frequency is 4.096 MHz. The clock is applied to
the CLK pin. The ADC data rates scale with CLK frequency, however there is no benefit in noise by reducing the
CLK frequency.
As with any high-speed data converter, a high-quality, low-jitter clock is essential for optimum performance.
Crystal clock oscillators are the recommended clock source. Make sure to avoid excess ringing on the clock
input; keep the clock trace as short as possible and use a 50-Ω series resistor close to the source.
Copyright © 2014–2019, Texas Instruments Incorporated
31
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
8.4 Device Functional Modes
8.4.1 Synchronization (SYNC PIN and SYNC Command)
The ADS1283 can be synchronized to an external event, as well as to other ADS1283 devices if the
synchronization is applied simultaneously.
The ADS1283 has two sources for synchronization: the SYNC input pin and the SYNC command. The ADS1283
also has two synchronizing modes: pulse-sync and continuous-sync. In pulse-sync mode, the ADS1283
synchronizes to a single synchronization. In continuous-sync mode, either a single synchronization is used to
synchronize conversions, or a continuous clock is applied to the pin with a period equal to integer multiples of the
data rate. When the periods of the SYNC input and the DRDY output do not match, the ADS1283 resynchronizes
and conversions are restarted.
8.4.1.1 Pulse-Sync Mode
In pulse-sync mode, when a synchronization occurs (by pin or command), the ADS1283 unconditionally stops
and restarts the conversion process. When the ADC synchronizes, the device resets the internal filter memory,
DRDY goes high, and after the digital filter has settled, new conversion data are available as shown in Figure 45
and Table 12.
tCSDL
CLK
tDR
SYNC
tSPWH
tSPWL
New Data Ready
DRDY
(Pulse-sync mode)
DOUT
(Pulse-sync mode)
New Data Ready
DRDY
(Continuous-sync mode)
DOUT
(Continuous-sync mode)
Figure 45. Pulse-Sync and Continuous-Sync Timing With Single Synchronization
Table 12. Pulse-Sync Timing for Figure 45 and Figure 46
PARAMETER
CLK rising edge to SYNC rising edge(1)
SYNC clock period(2)
MIN
30
1
MAX
–30
UNIT
ns
tCSDL
tSYNC
Infinite
n / fDATA
1 / fCLK
tSPWH, L
SYNC pulse width, high or low
Time for data ready (SINC filter)
Time for data ready (FIR filter)
2
See Table 13
tDR
62.98046875 / fDATA + 468 / fCLK
(1) CLK rising edge to SYNC rising edge timing must not occur within the specified time window.
(2) Continuous-sync mode; a free-running clock applied to the SYNC input without causing resynchronization. See Figure 46
32
Copyright © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
Table 13. tDR Time for Data Ready (Sinc Filter)
fDATA (kSPS)
fCLK CYCLES(1)
128
64
32
16
8
440
616
968
1672
2824
(1) For SYNC and WAKEUP commands, number of fCLK cycles from next rising CLK edge directly after
eighth rising SCLK edge to DRDY falling edge. For WAKEUP command only, subtract two fCLK cycles.
Table 13 is referenced by Table 12 and Table 15.
Observe the timing restriction of SYNC rising edge to CLK rising edge as shown in Figure 45 and Table 12.
Synchronization occurs on the next rising CLK edge after the rising edge of the SYNC, or after the eighth rising
SCLK edge when synchronized by command. To synchronize multiple ADCs, broadcast the command to the
ADCs simultaneously.
8.4.1.2 Continuous-Sync Mode
In continuous-sync mode, either a single synchronization pulse or a continuous clock may be applied. When a
single synchronization pulse is applied (rising edge), the device resynchronizes as it does in pulse-sync mode.
ADC resynchronization occurs only under the condition that the time from the previous rising edge of SYNC is
not a multiple of the conversion period. When resynchronization occurs in continuous-sync mode, DRDY
continues to toggle unaffected, and the DOUT output is held low until data are ready (63 DRDY periods later). At
the 63rd reading, conversion data are valid (when the conversion data are non-zero), as shown in Figure 45.
When a continuous clock is applied to the SYNC pin, the period must be an integral multiple of the output data
rate or the device resynchronizes. Note that synchronization results in the restarting of the digital filter and an
interruption of 63 readings (as shown in Table 12).
If a SYNC clock is applied to the ADC, the device resynchronizes only under the condition tSYNC ≠ N / fDATA
,
where N = 1, 2, 3, and so on. DRDY continues to output, but DOUT is held low until the new data are ready. If a
SYNC clock is applied and the clock period matches an integral multiple of the output data rate, the device freely
runs without resynchronization. Note that the phase of the applied clock and output data rate (DRDY) are not
aligned because of the initial delay of DRDY after the SYNC clock is first applied. Figure 46 shows the timing for
continuous-sync mode.
tCSDL
CLK
tSPWH
SYNC
tSPWL
tSYNC
DRDY
1/fDATA
Figure 46. Continuous-Sync Timing With SYNC Clock
Apply a SYNC clock input after the continuous-sync mode is set. The first rising edge of SYNC then causes a
synchronization. Note that subsequent writes to any ADC register results in resynchronization at the time of the
register write operation. The resynchronization leads to loss of the SYNC-pin controlled synchronization
performed previously. Send the STANDBY command followed by the WAKEUP command to reestablish the
SYNC-pin synchronization. Resynchronization to the SYNC pin occurs as long as the time between the
STANDBY and WAKEUP commands is not a multiple integer of the conversion period by at least one clock
cycle.
Copyright © 2014–2019, Texas Instruments Incorporated
33
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
8.4.2 Reset (RESET Pin and Reset Command)
The ADS1283 can be reset in two ways: toggle the RESET pin low, or send a RESET command. When using
the RESET pin, take it low and hold for at least 2 / fCLK to force a reset. The ADS1283 is held in reset until the
pin is released. By command, reset takes effect on the next rising edge of fCLK after the eighth rising edge of
SCLK of the command. In order to make certain that the RESET command can function, the SPI interface may
need to be reset; see the Serial Interface section.
When the ADS1283 is reset, registers are set to default and the conversions are synchronized on the next rising
edge of CLK. New conversion data are available, as shown in Figure 47 and Table 14.
Settled
Data
DRDY
tDR
tCRHD
System Clock
(fCLK)
tRCSU
tRST
RESET Pin
or
RESET Command
Figure 47. Reset Timing
Table 14. Reset Timing for Figure 47
PARAMETER
MIN
UNIT
ns
tCRHD
tRCSU
tRST
CLK to RESET hold time
RESET to CLK setup time
RESET low
10
10
ns
2
1 / fCLK
s
tDR
Time for data ready
62.98046875 / fDATA + 468 / fCLK
34
Copyright © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
8.4.3 Power-Down (PWDN Pin and STANDBY Command)
There are two ways to power-down the ADS1283: take the PWDN pin low, or send a STANDBY command.
When the PWDN pin is pulled low, the internal circuitry is disabled to minimize power and the contents of the
register settings are reset.
When in a power-down state, the device outputs remain active and the device inputs must not float. When the
STANDBY command is sent, the SPI port and the configuration registers are kept active. Figure 48 and Table 15
show the timing. Standby mode is cancelled when CS is taken high.
PWDN Pin
Wakeup
Command
DRDY
tDR
Figure 48. PWDN Pin and Wake-Up Command Timing
(Table 15 shows tDR
)
Table 15. Power-On, PWDN Pin, and Wake-Up Command Timing for New Data
PARAMETER
FILTER MODE
See Table 13
SINC(1)
Time for data ready 216 CLK cycles after power-on;
and new data ready after PWDN pin or WAKEUP command
tDR
62.98046875 / fDATA + 468 / fCLK
FIR
(2)
(1) Supply power-on and PWDN pin default is 1000 SPS FIR.
(2) Subtract two CLK cycles for the WAKEUP command. The WAKEUP command is timed from the next rising edge of CLK to after the
eighth rising edge of SCLK during command to DRDY falling.
8.4.4 Power-On Sequence
The ADS1283 has three power supplies: AVDD, AVSS, and DVDD. Figure 49 shows the power-on sequence of
the ADS1283. The power supplies can be sequenced in any order. The supplies [the difference of (AVDD –
AVSS) and DVDD] generate signals that are ANDed together for the internal reset. After the supplies have
crossed the minimum thresholds, 216 fCLK cycles are counted before releasing the internal reset. After the internal
reset is released, new conversion data are available, as shown in Figure 49 and Table 15.
3.5V nom
AVDD - AVSS
1V nom
DVDD
CLK
16
2
fCLK
Internal Reset
DRDY
tDR
Figure 49. Power-On Sequence
Copyright © 2014–2019, Texas Instruments Incorporated
35
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
8.4.5 DVDD Power Supply
The DVDD supply operates over the range of 1.65 V to 3.6 V. If operating DVDD at less than 2.25 V, connect the
DVDD pin to the BYPAS pin. Otherwise, do not connect these pins together. Figure 50 shows this connection.
1.65 V to 3.6 V
DVDD
1 µF
Connect DVDD to BYPAS if DVDD is < 2.25 V.
Otherwise, do not connect these pins together.
BYPAS
1 µF
Figure 50. DVDD Power
8.4.6 Serial Interface
A serial interface is used to read both the conversion data and to access the configuration registers. The
interface is SPI-compatible and consists of four signals: CS, SCLK, DIN, and DOUT. A minimum of 16 ADCs
converting at 4 kSPS can share a common serial bus when operating SCLK at 2 MHz.
8.4.6.1 Chip Select (CS)
Chip select (CS) is an active-low input that enables the ADC serial interface for data transfer. When CS is low,
the serial interface is enabled for communication. When CS is high, the serial interface is disabled. When the
serial interface is disabled, the DOUT (output data pin) is high impedance (tristate or Hi-Z). When CS is high,
SCLK activity is ignored, and data transfers or commands in progress are reset. CS must remain low for the
duration of the data transfer with the ADC. CS can be tied low, which permanently enables the ADC serial
interface. When CS goes high, the ADC idles (STANDBY) and stop read data continuous (SDATAC) modes are
cancelled. See the SDATAC Requirements section for more information about SDATAC mode.
8.4.6.2 Serial Clock (SCLK)
The serial clock (SCLK) is an input pin that is used to clock data into (DIN) and out of (DOUT) the ADC. SCLK is
a Schmitt-trigger input that has a high degree of noise immunity. However, keep SCLK as clean as possible to
prevent possible glitches from inadvertently shifting the data.
Data are shifted into DIN on the rising edge of SCLK and data are shifted out of DOUT on the falling edge of
SCLK. Keep SCLK low when not active. SCLK is ignored when CS is high.
8.4.6.3 Data Input (DIN)
The data input pin (DIN) is used to input register data and commands to the ADS1283. Keep DIN low when
reading conversion data in the read-data-continuous mode (except when issuing a SDATAC command). Data on
DIN are shifted into the converter on the rising edge of SCLK.
8.4.6.4 Data Output (DOUT)
The data output pin (DOUT) is used to output data from the ADS1283. Data are shifted out on the falling edge of
SCLK. When CS is high, the DOUT pin is in tristate.
36
Copyright © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
8.4.6.5 Serial Port Auto Timeout
The serial interface is reset each time CS is taken high. However, for applications that tie CS low, the serial port
cannot be reset by taking CS high; reset of the serial interface is no longer possible by using CS. The ADS1283
provides a feature that automatically recovers the interface when a transmission is stopped or interrupted, or if an
inadvertent glitch appears on SCLK. To reset the serial interface, hold SCLK low for 64 DRDY cycles. The reset
of the serial interface results in termination of data transfer or commands in progress. After serial port reset
occurs, the next SCLK pulse starts a new communication cycle. To prevent automatic reset from occurring, pulse
SCLK at least once for every 64 DRDY pulses.
8.4.6.6 Data Ready (DRDY)
DRDY is an output that is driven low when new conversion data are ready, as shown in Figure 51. When reading
data in continuous mode, the read operation must be completed before four CLK periods before the next falling
DRDY goes low again, or the data are overwritten with new conversion data. When reading data in command
mode, the read operation can overlap the occurrence of the next DRDY without data corruption.
DRDY
DOUT
SCLK
Bit 31
Bit 30
Bit 29
Figure 51. DRDY With Data Retrieval
DRDY resets high on the first falling edge of SCLK. Figure 51 and Figure 52 show the function of DRDY with and
without data readback, respectively.
If data are not retrieved (no SCLK provided), DRDY pulses high for four fCLK periods during the update time, as
shown in Figure 52.
DRDY remains active when CS is high.
Data Updating
4/fCLK
DRDY
Figure 52. DRDY With No Data Retrieval
Copyright © 2014–2019, Texas Instruments Incorporated
37
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
8.4.7 Data Format
The ADS1283 output data is 32-bits in binary twos complement format, as shown in Table 16. The LSB of the
data is a redundant sign bit: 0 for positive numbers and 1 for negative numbers. However, when the output is
clipped to +FS, the LSB = 1, and when the output is clipped to –FS, the LSB = 0. If desired, the data readback
can be stopped at 24 bits. Note that in sinc-filter mode, the output data are scaled by ½.
Table 16. Ideal Output Code Versus Input Signal
32-BIT IDEAL OUTPUT CODE(1)
INPUT SIGNAL VIN
(AINP – AINN)
FIR FILTER
SINC FILTER(2)
VREF
(3)
>
7FFFFFFFh
See note
2 x PGA
VREF
2 x PGA
7FFFFFFEh
3FFFFFFFh
VREF
2PGA ´ (230 - 1)
00000002h
00000000h
FFFFFFFFh
00000001h
00000000h
FFFFFFFFh
0
-VREF
2PGA ´ (230 - 1)
230
-VREF
´
80000001h
80000000h
C0000000h
230 - 1
2PGA
230
-VREF
(3)
<
´
See note
230 - 1
2PGA
(1) Excludes effects of noise, linearity, offset, and gain errors.
(2) Due to the reduction in oversampling ratio (OSR) related to high data rates of the sinc filter, full resolution may not be available.
(3) In sinc-filter mode, the output does not clip at half-scale code when the full-scale range is exceeded.
38
Copyright © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
8.4.8 Reading Data
The ADS1283 provides two modes to read conversion data: read-data-continuous and read-data-by-command.
8.4.8.1 Read-Data-Continuous Mode
In the read-data-continuous mode, the conversion data are shifted out directly from the device without the need
for sending a read command. This mode is the default mode at power-on. This mode is also enabled by the
RDATAC command. When DRDY goes low, indicating that new data are available, the MSB of data appears on
DOUT, as shown in Figure 53. The data are normally read on the rising edge of SCLK, at the occurrence of the
first falling edge of SCLK, DRDY returns high. After 32 bits of data have been shifted out, further SCLK
transitions cause DOUT to go low. If desired, the read operation may be stopped at 24 bits. The data shift
operation must be completed within four CLK periods before DRDY falls again or the data may be corrupted.
When a SDATAC command is issued, the DRDY output is blocked but the ADS1283 continues conversions. In
stop continuous mode, the data can only be read by command.
CS(1)
DRDY
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 25 26 27 28 29 30 31 32
SCLK
DOUT(2)
DIN
Data Byte 1 (MSB)
tDDPD
Data Byte 2 (MSB - 1)
Data Byte 4 (LSB)
(1) DOUT is in tristate when CS is high. CS can be tied low. See Figure 1 for CS low to valid DOUT propagation time.
Figure 53. Read Data Continuous
Table 17. Timing Data for Figure 53
PARAMETER
MIN
TYP
MAX
UNIT
tDDPD
DRDY to valid MSB on DOUT propagation delay(1)
100
ns
(1) DOUT is in tristate when CS is high. Load on DOUT = 20 pF || 100 kΩ.
8.4.8.2 Read-Data-By-Command Mode
Read-data-continuous mode is stopped by the SDATAC command and put into read-data-by-command mode. In
read-data-by-command mode, an RDATA command must be sent to the device for each data conversion (as
shown in Figure 54). When the read data command is received (on the eighth SCLK rising edge), data are
available to read only when DRDY goes low (tDR). When DRDY goes low, conversion data appear on DOUT. The
data may be read on the rising edge of SCLK.
CS(1)
DRDY
tDR
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 33 34 35 36 37 38 39 40
SCLK
DOUT(2)
DIN
Don't Care
Command Byte (0001 0010)
Data Byte 1 (MSB)
tDDPD
Date Byte 4 (LSB)
(1) DOUT is in tristate when CS is high.CS can be tied low. See Figure 1 for CS low to SCLK rising edge time.
Figure 54. Read Data By Command, RDATA (tDDPD timing is given in Table 17)
Table 18. Read Data Timing for Figure 54
PARAMETER
DESCRIPTION
MIN
TYP
MAX
UNIT
tDR
Time for new data after data read command
0
1
fDATA
Copyright © 2014–2019, Texas Instruments Incorporated
39
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
8.4.9 One-Shot Operation
The ADS1283 can perform very power-efficient, one-shot conversions using the STANDBY command while
under software control. Figure 55 shows this sequence. First, issue the STANDBY command to set the standby
mode.
When ready to make a measurement, issue the WAKEUP command. When DRDY goes low, the fully-settled
conversion data are ready and can be read directly in read-data-continuous mode. Afterwards, issue another
STANDBY command. When ready for the next measurement, repeat the cycle starting with another WAKEUP
command.
ADC Status
Standby
Performing One-Shot Conversion
Standby
CS
DRDY
(1)
STANDBY
WAKEUP
DIN
STANDBY
DOUT
Settled
Data
See Figure 48 and Table 15 for time to new data.
Figure 55. One-Shot Conversions Using the STANDBY Command
8.4.10 Offset and Full-Scale Calibration Registers
The conversion data can be scaled for offset and gain before yielding the final output code. As shown in
Figure 56, the output of the digital filter is first subtracted by the offset register (OFC) and then multiplied by the
full-scale register (FSC). Equation 15 shows the scaling:
FSC[2:0]
Final Output Data = (Input - OFC[2:0]) ´
400000h
(15)
The values of the offset and full-scale registers are set by writing to them directly, or they are set automatically
by the calibration commands.
The offset and full-scale calibrations apply to specific PGA settings. When the PGA is changed, these registers
generally require recalculation. Calibration is bypassed in the sinc filter mode.
AINP
AINN
+
Output Data
Clipped to 32 Bits
Digital
Filter
´
Final Output
S
Modulator
-
OFC
Register
FSC Register
400000h
Figure 56. Calibration Block Diagram
40
Copyright © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
8.4.10.1 OFC[2:0] Registers
The 24-bit offset calibration word is composed of three 8-bit registers, as shown in Table 19. The offset register
is left-justified to align with the 32 bits of conversion data. The offset is in twos complement format with a
maximum positive value of 7FFFFFh and a maximum negative value of 800000h. This value is subtracted from
the conversion data. A register value of 00000h has no offset correction (default value).
Table 19. Offset Calibration Word
REGISTER
OFC0
BYTE
LSB
BIT ORDER
B7
B15
B6
B5
B4
B3
B2
B1
B9
B0 (LSB)
B8
OFC1
MID
B14
B22
B13
B21
B12
B20
B11
B19
B10
B18
OFC2
MSB
B23 (MSB)
B17
B16
Although the offset calibration register value can correct offsets ranging from –FS to +FS (as shown in Table 20),
in order to avoid input overload, do not exceed the maximum input voltage range of 106% FSR (including
calibration).
Table 20. Offset Calibration Values
OFC REGISTER
7FFFFFh
FINAL OUTPUT CODE(1)
80000000h
000001h
FFFFFF00h
000000h
00000000h
FFFFFFh
800000h
00000100h
7FFFFF00h
(1) Full 32-bit final output code with zero code input.
8.4.10.2 FSC[2:0] Registers
The full-scale calibration is a 24-bit word, composed of three 8-bit registers, as shown in Table 21. The full-scale
calibration value is 24-bit, straight offset binary, normalized to 1.0 at code 400000h.
Table 21. Full-Scale Calibration Word
REGISTER
FSC0
BYTE
LSB
BIT ORDER
B7
B15
B6
B5
B4
B3
B2
B1
B9
B0 (LSB)
B8
FSC1
MID
B14
B22
B13
B21
B12
B20
B11
B19
B10
B18
FSC2
MSB
B23 (MSB)
B17
B16
Table 22 summarizes the scaling of the full-scale register. A register value of 400000h (default value) has no
gain correction (gain = 1). Although the full-scale calibration register value corrects gain errors above one (gain
correction < 1), the full-scale range of the analog inputs must not exceed 106% FSR (including calibration) in
order to avoid input overload.
Table 22. Full-Scale Calibration Register Values
FSC REGISTER
800000h
GAIN CORRECTION
2.0
1.0
0.5
0
400000h
200000h
000000h
Copyright © 2014–2019, Texas Instruments Incorporated
41
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
8.4.11 Calibration Commands (OFSCAL and GANCAL)
Use the calibration commands (OFSCAL or GANCAL) to calibrate the conversion data. The values of the offset
and gain calibration registers are internally written to perform calibration. The appropriate input signals must be
applied to the ADS1283 inputs before sending the commands. Use slower data rates to achieve more consistent
calibration results; this effect is a byproduct of the lower noise that these data rates provide. Also, if calibrating at
power-on, be sure the reference voltage is fully settled.
Figure 57 shows the calibration command sequence. After the analog input voltage (and reference) have
stabilized, send the SDATAC command, followed by the SYNC and RDATAC commands. DRDY goes low after
64 data periods. After DRDY goes low, send the SDATAC command, then the calibrate command (OFSCAL or
GANCAL), followed by the RDATAC command. After 16 data periods, calibration is complete and conversion
data can be read at this time. The SYNC input must remain high during the calibration sequence.
VIN
Fully stable input and reference voltage.
OFSCAL or
Commands
SDATAC
SYNC
RDATAC
SDATAC
RDATAC
GANCAL
Calibration
Complete
16 Data
Periods
DRDY
SYNC
64 Data Periods
Figure 57. Offset and Gain Calibration Timing
The calibration commands apply to specific PGA settings. If the PGA is changed, recalibration is necessary.
Calibration is bypassed in the sinc filter mode.
8.4.11.1 OFSCAL Command
The OFSCAL command performs an offset calibration. Before sending the OFSCAL command sequence
(Figure 57), a zero input signal must be applied to the ADS1283 and the inputs allowed to stabilize. When the
command sequence (Figure 57) is sent, the ADS1283 averages 16 readings, and then writes this value to the
OFC register. The contents of the OFC register can be subsequently read or written. During offset calibration, the
full-scale correction is bypassed. Use the OFSCAL command to calibrate the optional 100-mV offset.
8.4.11.2 GANCAL Command
The GANCAL command performs a gain calibration. Before sending the GANCAL command sequence
(Figure 57), a dc input must be applied (typically full-scale input, but not to exceed 106% full-scale). After the
signal has stabilized, the command sequence can be sent. The ADS1283 averages 16 readings, then computes
a gain value that scales the applied calibration voltage to full-scale. The gain value is written to the FSC register,
where the contents are subsequently read or written.
42
Copyright © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
8.4.12 User Calibration
System calibration of the ADS1283 can be performed without using the calibration commands. This procedure
requires the calibration values to be externally calculated and then written to the calibration registers. The steps
for this procedure are:
1. Set the OFSCAL[2:0] register = 0h, and GANCAL[2:0] = 400000h. These values set the offset and gain
registers to 0 and 1, respectively.
2. Apply a zero differential input to the input of the system. Wait for the system to settle and then average the
output readings. Higher numbers of averaged readings result in more consistent calibration. Write the
averaged value to the OFC register.
3. Apply a differential dc signal, or an ac signal (typically full-scale, but do not exceed 106% FSR). Wait for the
system to settle and then average the output readings.
The value written to the FSC registers is calculated by Equation 16 or Equation 17.
DC-signal calibration is shown in Equation 16. The expected output code is based on 31-bit output data.
Expected Output Code
FSC[2:0] = 400000h ´
Actual Output Code
(16)
For ac-signal calibration, use an RMS value of collected data, as shown in Equation 17:
Expected RMS Value
FSC[2:0] = 400000h ´
Actual RMS Value
(17)
Copyright © 2014–2019, Texas Instruments Incorporated
43
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
8.5 Programming
8.5.1 Commands
The commands listed in Table 23 control the operation of the ADS1283. Most commands are stand-alone (that
is, one byte in length); the register read and write commands are two bytes long in addition to the actual register
data bytes.
Table 23. Command Descriptions
COMMAND
WAKEUP
STANDBY
SYNC
TYPE
Control
Control
Control
Control
Control
Control
Data
DESCRIPTION
Wake-up from standby mode
1st COMMAND BYTE(1)(2)
0000 000X (00h or 01h)
0000 001X (02h or 03h)
0000 010X (04h or 5h)
0000 011X (06h or 07h)
0001 0000 (10h)
2nd COMMAND BYTE(3)
Enter standby mode
Synchronize the analog-to-digital conversion
Reset registers to default values
Enter read data continuous mode
Stop read data continuous mode
Read data by command(4)
RESET
RDATAC
SDATAC
RDATA
0001 0001 (11h)
0001 0010 (12h)
RREG
Register
Register
Read nnnnn register(s) at address rrrrr(4)
001r rrrr (20h + 000r rrrr)
010r rrrr (40h + 000r rrrr)
0110 0000 (60h)
000n nnnn (00h + n nnnn)
000n nnnn (00h + n nnnn)
WREG
Write nnnnn register(s) at address rrrrr
OFSCAL
GANCAL
Calibration Offset calibration
Calibration Gain calibration
0110 0001 (61h)
(1) X = don't care.
(2) rrrrr = starting address for register read and write commands.
(3) nnnnn = number of registers to be read from or written to – 1. For example, to read from or write to three registers, set nnnnn = 2
(00010).
(4) Required to cancel read-data-continuous mode before sending a command.
CS must remain low for duration of the command-byte sequence. A delay of 24 fCLK cycles between commands
and between bytes within a command is required, starting from the last SCLK rising edge of one command to the
first SCLK rising edge of the following command. The required delay is shown in Figure 58.
CS
Command
Byte
Command
Byte
DIN
SCLK
(1)
(1)
tSCLKDLY
tSCLKDLY
(1) tSCLKDLY = 24 / fCLK (min).
Figure 58. Consecutive Commands
8.5.1.1 SDATAC Requirements
In read-data-continuous mode, the ADS1283 places conversion data on the DOUT pin as SCLK is applied. As a
result of the potential conflict between conversion data and register data placed on DOUT resulting from a RREG
or RDATA operation, it is necessary to send a stop-read-data-continuous (SDATAC) command before a RREG
or RDATA command. The SDATAC command disables the direct output of conversion data on the DOUT pin.
CS = 1 cancels SDATAC mode; therefore, keep CS held low after sending the SDATAC command to the next
RREG or RDATA command.
44
Copyright © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
8.5.1.2 WAKEUP: Wake-Up From Standby Mode
The WAKEUP command is used to exit the standby mode. After sending this command, the time for the first data
to be ready is illustrated in Figure 48 and Table 16. Sending this command during normal operation has no
effect; for example, reading data by the read-data-continuous mode with DIN held low.
8.5.1.3 STANDBY: Standby Mode
The STANDBY command places the ADS1283 into standby mode. In standby, the device enters a reduced
power state where a low quiescent current remains to keep the register settings and serial interface active. The
ADC remains in standby mode until CS is taken high or the WAKEUP command is sent. For complete device
shutdown, take the PWDN pin low (register settings are not saved). The operation of standby mode is shown in
Figure 59.
0000 001X
(STANDBY)
0000 000X
(WAKEUP)
DIN
SCLK
Operating
Standby Mode
Operating
Figure 59. STANDBY Command Sequence
8.5.1.4 SYNC: Synchronize the Analog-to-Digital Conversion
The SYNC command synchronizes the analog-to-digital conversion. Upon receiving the command, the reading in
progress is cancelled and the conversion process is restarted. In order to synchronize multiple ADS1283s, the
command must be sent simultaneously to all devices. The SYNC pin must be held high during this command.
8.5.1.5 RESET: Reset the Device
The RESET command resets the registers to default values, enables read-data-continuous mode, and restarts
the conversion process. The RESET command is functionally equivalent to taking the RESET pin low. See
Figure 47 for the RESET command timing.
8.5.1.6 RDATAC: Read Data Continuous
The RDATAC command enables read-data-continuous mode (default mode). In this mode, conversion data is
read from the device directly without the need to supply a data read command. Each time DRDY falls low, new
data are available to read. See the Read-Data-Continuous Mode section for more details.
8.5.1.7 SDATAC: Stop Read Data Continuous
The SDATAC command stops read-data-continuous mode. Exit read-data-continuous mode before sending
register and data read commands. The SDATAC command suppresses the DRDY output, but the ADS1283
continues conversions. Take CS high to cancel SDATAC mode.
Copyright © 2014–2019, Texas Instruments Incorporated
45
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
8.5.1.8 RDATA: Read Data by Command
The RDATA command reads the conversion data. See the Read-Data-By-Command Mode section for more
details.
8.5.1.9 RREG: Read Register Data
The RREG command is used to read single- or multiple-register data. The command consists of a two-byte
opcode argument, followed by the output of register data. The first byte of the opcode includes the starting
address, and the second byte specifies the number of registers to read minus one.
First command byte: 001r rrrr, where rrrrr is the starting address of the first register.
Second command byte: 000n nnnn, where nnnnn is the number of registers to read minus one.
Starting with the 16th falling edge of SCLK, the register data appear on DOUT. Read the data on the 17th SCLK
rising edge.
The RREG command is illustrated in Figure 60.
A delay of 24 fCLK cycles is required between each byte transaction.
CS(1)
tDLY
tDLY
tDLY
25 26
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16
17 18 19 20 21 22 23 24
SCLK
DIN
Command Byte 1
Command Byte 2
DOUT(2)
Don't Care
Register Data 5
Register Data 6
Example: Read six registers, starting at register 05h (OFC0)
Command Byte 1 = 0010 0101
Command Byte 2 = 0000 0101
(1) DOUT is in tristate when CS is high. CS can be tied low. See Figure 1 for CS low to SCLK rising edge time.
Figure 60. Read Register Data (Table 24 shows tDLY
)
Table 24. tDRY Value
PARAMETER
MIN
tDLY
24 / fCLK
46
Copyright © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
8.5.1.10 WREG: Write to Register
The WREG command writes single- or multiple-register data. The command consists of a two-byte op-code
argument followed by the input of register data. The first byte of the op-code contains the starting address and
the second byte specifies the number of registers to write minus one.
First command byte: 010r rrrr, where rrrrr is the starting address of the first register.
Second command byte: 000n nnnn, where nnnnn is the number of registers to write minus one.
Data byte(s): one or more register data bytes, depending on the number of registers specified.
Figure 61 illustrates the WREG command.
A delay of 24 fCLK cycles is required between each byte transaction.
CS(1)
tDLY
tDLY
tDLY
25 26
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16
17 18 19 20 21 22 23 24
SCLK
DIN
Register Data 6
Command Byte 1
Command Byte 2
Register Data 5
Example: Write six registers, starting at register 05h (OFC0)
Command Byte 1 = 0100 0101
Command Byte 2 = 0000 0101
(1) CS can be tied low. See Figure 1 for CS low to SCLK rising edge time.
Figure 61. Write Register Data (Table 24 shows tDLY
)
8.5.1.11 OFSCAL: Offset Calibration
The OFSCAL command performs an offset calibration. The inputs to the converter (or the inputs to the external
preamplifier) should be zeroed and allowed to stabilize before sending this command. The offset calibration
register updates after this operation. See the Calibration Commands section for more details.
8.5.1.12 GANCAL: Gain Calibration
The GANCAL command performs a gain calibration. The inputs to the converter should have a stable dc input
(typically full-scale, but not to exceed 106% full-scale). The gain calibration register updates after this operation.
See the Calibration Commands section for more details.
Copyright © 2014–2019, Texas Instruments Incorporated
47
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
8.6 Register Maps
Collectively, the registers contain all the information needed to configure the device, such as data rate, filter
selection, calibration, and more. The registers are accessed by the RREG and WREG commands. The registers
can be accessed individually or as a block of registers by sending or receiving consecutive bytes. After a register
write operation, the ADC resets, resulting in an interruption of 63 readings.
Table 25. Register Map
RESET
ADDRESS
00h
REGISTER
ID_CFG
CONFIG0
CONFIG1
HPF0
VALUE
X0h
52h
08h
32h
03h
00h
00h
00h
00h
00h
40h
BIT 7
ID3
BIT 6
ID2
BIT 5
ID1
BIT 4
ID0
BIT 3
0
BIT 2
0
BIT 1
OFFSET1
FILTR1
PGA1
BIT 0
OFFSET0
FILTR0
PGA0
01h
SYNC
0
1
DR2
DR1
DR0
PHASE
PGA2
HPF02
HPF10
OFC02
OFC10
OFC18
FSC02
FSC10
FSC18
02h
MUX2
HPF06
HPF14
OFC06
OFC14
OFC22
FSC06
FSC14
FSC22
MUX1
HPF05
HPF13
OFC05
OFC13
OFC21
FSC05
FSC13
FSC21
MUX0
HPF04
HPF12
OFC04
OFC12
OFC20
FSC04
FSC12
FSC20
CHOP
HPF03
HPF11
OFC03
OFC11
OFC19
FSC03
FSC11
FSC19
03h
HPF07
HPF15
OFC07
OFC15
OFC23
FSC07
FSC15
FSC23
HPF01
HPF09
OFC01
OFC09
OFC17
FSC01
FSC09
FSC17
HPF00
HPF08
OFC00
OFC08
OFC16
FSC00
FSC08
FSC16
04h
HPF1
05h
OFC0
06h
OFC1
07h
OFC2
08h
FSC0
09h
FSC1
0Ah
FSC2
8.6.1 Register Descriptions
8.6.1.1 ID_CFG: ID_Configuration Register (address = 00h) [reset =x0h]
Figure 62. ID_CFG Register
7
6
5
4
3
0
2
0
1
0
ID3
R-xh
ID2
R-xh
ID1
R-xh
ID0
R-xh
OFFSET1
R/W-0h
OFFSET0
R/W-0h
R/W-0h
R/W-0h
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Bit[7:4]
ID[3:0]
Factory-programmed identification bits (read-only). The ID bits are subject to change
without notification.
Bit[3:2]
Bit[1:0]
Reserved
Always write 00
OFFSET[1:0] (see Offset section)
00: Disables offset (default)
01: Reserved
10: Offset = 100/PGA mV (all ADS1283 versions)
11: Offset = 75/PGA mV (ADS1283B only)
48
Copyright © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
8.6.1.2 CONFIG0: Configuration Register 0 (address = 01h) [reset = 52h]
Figure 63. CONFIG0 Register
7
6
1
5
4
3
2
1
0
SYNC
R/W-0h
DR2
DR1
DR0
PHASE
R/W-0h
FILTR1
R/W -1h
FILTR0
R/W-0h
R/W-1h
R/W-0h
R/W-1h
R/W-0h
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Bit[7]
SYNC
Synchronization mode bit.
0: Pulse-sync mode (default)
1: Continuous-sync mode
Bit[6]
RESERVED
Always write 1
DR[2:0]
Bit[5:3]
Data rate select bits.
000: 250 SPS
001: 500 SPS
010: 1000 SPS (default)
011: 2000 SPS
100: 4000 SPS
Bit[2]
PHASE
FIR phase response bit.
0: Linear phase (default)
1: Minimum phase
Bit[1:0]
FILTR[1:0]
Digital filter configuration bits.
00: Reserved
01: Sinc filter block only
10: Sinc + LPF filter blocks (default)
11: Sinc + LPF + HPF filter blocks
Copyright © 2014–2019, Texas Instruments Incorporated
49
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
8.6.1.3 CONFIG1: Configuration Register 1 (address = 02h) [reset = 08h]
Figure 64. CONFIG1 Register
7
0
6
5
4
3
2
1
0
MUX2
R/W-0h
MUX1
R/W-0h
MUX0
R/W-0h
CHOP
R/W-1h
PGA2
R/W-0h
PGA1
R/W-0h
PGA0
R/W-0h
R/W-0h
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Bit[7]
Reserved
Always write 0
MUX[2:0]
Bit[6:4]
MUX select bits.
000: AINP1 and AINN1 (default)
001: AINP2 and AINN2
010: Internal short through 400-Ω resistor
011: AINP1 and AINN1 connected to AINP2 and AINN2
100: External short to AINN2
Bit[3]
CHOP
PGA chopping enable bit.
0: PGA chopping disabled
1: PGA chopping enabled (default)
Bit[2:0]
PGA[2:0]
PGA gain select bits. Note that ADS1283A supports PGA gains of 1, 4, and 16 only.
000: G = 1 (default)
001: G = 2 (ADS1283 and ADS1283B only)
010: G = 4
011: G = 8 (ADS1283 and ADS1283B only)
100: G = 16
101: G = 32 (ADS1283 and ADS1283B only)
110: G = 64 (ADS1283 and ADS1283B only)
8.6.1.4 HPF0 and HPF1 Registers
These two bytes (high-byte and low-byte, respectively) set the corner frequency of the high-pass filter.
8.6.1.4.1 HPF0: High-Pass Filter Corner Frequency, Low Byte (address = 03h) [reset = 32h]
Figure 65. HPF0 Register
7
6
5
4
3
2
1
0
HPF07
R/W-0h
HPF06
R/W-0h
HPF05
R/W-1h
HPF04
R/W-1h
HPF03
R/W-0h
HPF02
R/W-0h
HPF01
R/W-1h
HPF00
R/W-0h
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
8.6.1.4.2 HPF1: High-Pass Filter Corner Frequency, High Byte (address = 04h) [reset = 03h]
Figure 66. HPF1 Register
7
6
5
4
3
2
1
0
HPF15
R/W-0h
HPF14
R/W-0h
HPF13
R/W-0h
HPF12
R/W-0h
HPF11
R/W-0h
HPF10
R/W-0h
HPF09
R/W-1h
HPF08
1R/W-1h
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
50
Copyright © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
8.6.1.5 OFC0, OFC1, OFC2 Registers
These three bytes set the offset calibration value.
8.6.1.5.1 OFC0: Offset Calibration, Low Byte (address = 05h) [reset = 00h]
Figure 67. OFC0 Register
7
6
5
4
3
2
1
0
OFC07
R/W-0h
OFC06
R/W-0h
OFC05
R/W-0h
OFC04
R/W-0h
OFC03
R/W-0h
OFC02
R/W-0h
OFC01
R/W-0h
OFC00
R/W-0h
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
8.6.1.5.2 OFC1: Offset Calibration, Mid Byte (address = 06h) [reset = 00h]
Figure 68. OFC1 Register
7
6
5
4
3
2
1
0
OFC15
R/W-0h
OFC14
R/W-0h
OFC13
R/W-0h
OFC12
R/W-0h
OFC11
R/W-0h
OFC10
R/W-0h
OFC09
R/W-0h
OFC08
R/W-0h
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
8.6.1.5.3 OFC2: Offset Calibration, High Byte (address = 07h) [reset = 00h]
Figure 69. OFC2 Register
7
6
5
4
3
2
1
0
OFC23
R/W-0h
OFC22
R/W-0h
OFC21
R/W-0h
OFC20
R/W-0h
OFC19
R/W-0h
OFC18
R/W-0h
OFC17
R/W-0h
OFC16
R/W-0h
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
8.6.1.6 FSC0, FSC1, FSC2 Registers
These three bytes set the full-scale calibration value.
8.6.1.6.1 FSC0: Full-Scale Calibration, Low Byte (address = 08h) [reset = 00h]
Figure 70. FSC0 Register
7
6
5
4
3
2
1
0
FSC07
R/W-0h
FSC06
R/W-0h
FSC05
R/W-0h
FSC04
R/W-0h
FSC03
R/W-0h
FSC02
R/W-0h
FSC01
R/W-0h
FSC00
R/W-0h
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
8.6.1.6.2 FSC1: Full-Scale Calibration, Mid Byte (address = 09h) [reset = 00h]
Figure 71. FSC1 Register
7
6
5
4
3
2
1
0
FSC15
R/W-0h
FSC14
R/W-0h
FSC13
R/W-0h
FSC12
R/W-0h
FSC11
R/W-0h
FSC10
R/W-0h
FSC09
R/W-0h
FSC08
R/W-0h
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
8.6.1.6.3 FSC2: Full-Scale Calibration, High Byte (address = 0Ah) [reset = 40h]
Figure 72. FSC2 Register
7
6
5
4
3
2
1
0
FSC23
R/W-0h
FSC22
R/W-1h
FSC21
R/W-0h
FSC20
R/W-0h
FSC19
R/W-0h
FSC18
R/W-0h
FSC17
R/W-0h
FSC16
R/W-0h
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Copyright © 2014–2019, Texas Instruments Incorporated
51
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
9 Application and Implementation
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
9.1 Application Information
The ADS1283 is a very high-resolution ADC. Optimal performance requires giving special attention to the
support circuitry and printed circuit board (PCB) design. Locate noisy digital components (such as
microcontrollers, oscillators, and so on) in an area of the PCB away from the converter and front-end
components. Keep the digital current path short and separate from sensitive analog components by placing the
digital components close to the power-entry point.
9.2 Typical Applications
9.2.1 Geophone Interface
A typical geophone front-end application is shown in Figure 73. The application diagram shows the ADS1283
operation with dual ±2.5-V analog supplies. The ADS1283 can also operate with a single 5-V analog supply.
+2.5V
-
2.5V
1 mF
AVDD
AVSS
AINP2
AINN2
Test
Signal
+2.5V
(1)
R1
R3
100 Ω
100 Ω
AINP1
AINN1
C2
R5
C4
10nF
C0G
1 nF, C0G
20 kΩ
Geophone
R6
R2
R4
C3
20 kΩ 100 Ω
100 Ω
1 nF, C0G
ADC
-2.5V
CAPP
CAPN
C6
10 nF
C0G
+3.3V
R7
1 kΩ
(2)
1 mF
VREFP
VREFN
REF5050
+
NR
C5
100 mF
C7
0.1 mF
1 mF
1 mF
DGND
-
2.5V
(1) Optional external diode clamps.
(2) Optional reference noise filter.
Figure 73. Geophone Interface Application
52
Copyright © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
Typical Applications (continued)
The geophone input signal is filtered by both a differential filter (components C4 and R1 to R4) and by common-
mode filters (components C2, C3 and R1, R2). The differential filter removes high-frequency normal-mode
components from the input signal. The common-mode filters remove high-frequency components that are
common to both input leads. The input filters are not required for all applications; check the system requirements
for each application.
Resistors R5 and R6 bias the signal input to the midsupply point (ground). For single-supply operation, set the
bias to a low impedance midsupply point (AVDD / 2 = 2.5 V).
Optional diode clamps protect the ADS1283 inputs from high-level voltage transients and overloads. The diodes
provide additional protection if possible high-level input transients and surges exceed the ADC internal ESD
diode rating.
The REF5050 5-V reference provides the reference to the ADC. An optional filter network (R7 and C5) reduces
the in-band reference noise for improved dynamic performance. However, the RC filter network increases the
filter settling-time (from seconds to possibly minutes) depending on the dielectric absorption properties of
capacitor C5. Capacitor C7 is mandatory and provides high-frequency bypassing of the reference inputs; place C7
as close as possible to the ADS1283 pins. Resistor R7 (1 kΩ) results in a 1% systematic gain error. Multiple
ADCs can share a single reference, but if shared, use independent reference filters for each ADC.
As an alternative, the REF5045 (4.5 V) reference can be used. The REF5045 reference has the advantage of
operating directly from the 5-V (total) power supply; however, the 4.5-V reference reduces signal range by 10%
and results in a 1-dB loss of SNR.
Capacitor C6 (10 nF) filters the PGA output glitches caused by sampling of the modulator. This capacitor also
forms an antialias filter with a low-pass cutoff frequency of 26 kHz.
Copyright © 2014–2019, Texas Instruments Incorporated
53
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
Typical Applications (continued)
9.2.2 Digital Interface
Figure 74 shows the digital connection to a controller (field programmable gate array or microcontroller). In this
example, two ADCs are shown connected to one controller. The ADCs share the same serial interface (SCLK,
DIN, and DOUT). The ADC is selected for communication by strobing each CS low. The DRDY output from both
ADCs can be used; however, when the devices are synchronized, the DRDY output from only one device is
sufficient.
Clock
ADC #1
Controller
47 Ω
(1)
+3.3V
DVDD
CLK
CLK (input)
47 Ω
47 Ω
RESET (output)
1 µF
1 µF
RESET
SYNC
SYNC (output)
SS1 (output)
47 Ω
47 Ω
47 Ω
BYPAS
CS
SCLK (output)
SCLK
DIN
DOUT
MOSI (output)
MISO (input)
47 Ω
47 Ω
47 Ω
MFLAG
MFLAG1 (input)
MFLAG2 (input)
DGND
ADC #2
47 Ω
47 Ω
SS2 (output)
DRDY (input)
(1)
DVDD
CLK
RESET
SYNC
+3.3V
1 µF
1 µF
BYPAS
CS
SCLK
DIN
DOUT
MFLAG
DRDY
DGND
(1) For DVDD < 2.25 V, tie DVDD and BYPASS together. see the DVDD Power Supply section.
Figure 74. Controller Interface with Dual ADCs
The modulator overrange flag (MFLAG) from each device ties to the controller input. For synchronization,
connect all ADCs to the same SYNC signal. For reset, either connect all ADCs to the same RESET signal or
connect the ADCs to individual RESET signals.
Avoid ringing on the digital inputs to the ADCs. Place 47-Ω resistors in series with the digital traces to help
reduce ringing by controlling impedances. Place the resistors at the source (driver) end of the trace. Do not float
unused digital inputs; tie them to DVDD or GND.
54
Copyright © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
9.3 Initialization Set Up
After reset or power-on, configure the registers using the following procedure:
1. Reset the serial interface. Before using the serial interface, it may be necessary to recover the serial
interface (undefined I/O power-up sequencing may cause a false SCLK to occur). To reset the interface,
toggle the CS pin high then low, or toggle the RESET pin high then low, or when in read-data-continuous
mode, hold SCLK low for 64 DRDY periods.
2. Configure the registers. The registers are configured by either writing to them individually or as a group,
and can be configured in either mode. To cancel read-data-continuous mode, send the SDATAC command
before register read and write operations .
3. Verify register data. For verification of device communications, read back the register.
4. Set the data mode. After register configuration, configure the device for read-data-continuous mode by
executing the RDATAC command, or configure for read-data-by-command mode (set in step 2, by the
SDATAC command).
5. Synchronize readings. Whenever SYNC is high, the ADS1283 freely runs the data conversions. To
resynchronize the conversions in pulse-sync mode, take SYNC low and then high. In continuous-sync mode,
apply the synchronizing clock to the SYNC pin with a clock period equal to multiples of the ADC conversion
period.
6. Read data. If read-data-continuous mode is active, the data are read directly after DRDY falls by applying
SCLK pulses. If the read-data-continuous mode is inactive, the data can only be read by executing the
RDATA command. The RDATA command must be sent in this mode to read each conversion result.
版权 © 2014–2019, Texas Instruments Incorporated
55
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
10 器件和文档支持
10.1 接收文档更新通知
要接收文档更新通知,请导航至 TI.com.cn 上的器件产品文件夹。单击右上角的通知我 进行注册,即可每周接收产
品信息更改摘要。有关更改的详细信息,请查看任何已修订文档中包含的修订历史记录。
10.2 社区资源
The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective
contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of
Use.
TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration
among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help
solve problems with fellow engineers.
Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and
contact information for technical support.
10.3 商标
E2E is a trademark of Texas Instruments.
SPI is a trademark of Motorola Inc.
All other trademarks are the property of their respective owners.
10.4 静电放电警告
ESD 可能会损坏该集成电路。德州仪器 (TI) 建议通过适当的预防措施处理所有集成电路。如果不遵守正确的处理措施和安装程序 , 可
能会损坏集成电路。
ESD 的损坏小至导致微小的性能降级 , 大至整个器件故障。 精密的集成电路可能更容易受到损坏 , 这是因为非常细微的参数更改都可
能会导致器件与其发布的规格不相符。
10.5 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
56
版权 © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
11 机械、封装和可订购信息
以下页面包含机械、封装和可订购信息。这些信息是指定器件的最新可用数据。数据如有变更,恕不另行通知,且
不会对此文档进行修订。如需获取此数据表的浏览器版本,请查阅左侧的导航栏。
版权 © 2014–2019, Texas Instruments Incorporated
57
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
58
版权 © 2014–2019, Texas Instruments Incorporated
ADS1283
www.ti.com.cn
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
版权 © 2014–2019, Texas Instruments Incorporated
59
ADS1283
ZHCSK66C –JANUARY 2014–REVISED AUGUST 2019
www.ti.com.cn
60
版权 © 2014–2019, Texas Instruments Incorporated
PACKAGE OPTION ADDENDUM
www.ti.com
10-Dec-2020
PACKAGING INFORMATION
Orderable Device
Status Package Type Package Pins Package
Eco Plan
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
Samples
Drawing
Qty
(1)
(2)
(3)
(4/5)
(6)
ADS1283AIRHFR
ADS1283AIRHFT
ADS1283BIRHFR
ADS1283BIRHFT
ADS1283IRHFR
ADS1283IRHFT
ACTIVE
VQFN
VQFN
VQFN
VQFN
VQFN
VQFN
RHF
24
24
24
24
24
24
3000 RoHS & Green
250 RoHS & Green
3000 RoHS & Green
250 RoHS & Green
3000 RoHS & Green
250 RoHS & Green
NIPDAU
Level-3-260C-168 HR
Level-3-260C-168 HR
Level-3-260C-168 HR
Level-3-260C-168 HR
Level-3-260C-168 HR
Level-3-260C-168 HR
-40 to 85
-40 to 85
-40 to 85
-40 to 85
-40 to 85
-40 to 85
ADS
1283A
ACTIVE
ACTIVE
ACTIVE
ACTIVE
ACTIVE
RHF
NIPDAU
NIPDAU
NIPDAU
NIPDAU
NIPDAU
ADS
1283A
RHF
ADS
1283B
RHF
ADS
1283B
RHF
ADS
1283
RHF
ADS
1283
(1) The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based
flame retardants must also meet the <=1000ppm threshold requirement.
(3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
(4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.
(5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation
of the previous line and the two combined represent the entire Device Marking for that device.
Addendum-Page 1
PACKAGE OPTION ADDENDUM
www.ti.com
10-Dec-2020
(6)
Lead finish/Ball material - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead finish/Ball material values may wrap to two
lines if the finish value exceeds the maximum column width.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
Addendum-Page 2
PACKAGE MATERIALS INFORMATION
www.ti.com
20-Apr-2023
TAPE AND REEL INFORMATION
REEL DIMENSIONS
TAPE DIMENSIONS
K0
P1
W
B0
Reel
Diameter
Cavity
A0
A0 Dimension designed to accommodate the component width
B0 Dimension designed to accommodate the component length
K0 Dimension designed to accommodate the component thickness
Overall width of the carrier tape
W
P1 Pitch between successive cavity centers
Reel Width (W1)
QUADRANT ASSIGNMENTS FOR PIN 1 ORIENTATION IN TAPE
Sprocket Holes
Q1 Q2
Q3 Q4
Q1 Q2
Q3 Q4
User Direction of Feed
Pocket Quadrants
*All dimensions are nominal
Device
Package Package Pins
Type Drawing
SPQ
Reel
Reel
A0
B0
K0
P1
W
Pin1
Diameter Width (mm) (mm) (mm) (mm) (mm) Quadrant
(mm) W1 (mm)
ADS1283AIRHFR
ADS1283AIRHFT
ADS1283BIRHFR
ADS1283BIRHFT
ADS1283IRHFR
ADS1283IRHFT
VQFN
VQFN
VQFN
VQFN
VQFN
VQFN
RHF
RHF
RHF
RHF
RHF
RHF
24
24
24
24
24
24
3000
250
330.0
180.0
330.0
180.0
330.0
180.0
12.4
12.4
12.4
12.4
12.4
12.4
4.3
4.3
4.3
4.3
4.3
4.3
5.3
5.3
5.3
5.3
5.3
5.3
1.3
1.3
1.3
1.3
1.3
1.3
8.0
8.0
8.0
8.0
8.0
8.0
12.0
12.0
12.0
12.0
12.0
12.0
Q1
Q1
Q1
Q1
Q1
Q1
3000
250
3000
250
Pack Materials-Page 1
PACKAGE MATERIALS INFORMATION
www.ti.com
20-Apr-2023
TAPE AND REEL BOX DIMENSIONS
Width (mm)
H
W
L
*All dimensions are nominal
Device
Package Type Package Drawing Pins
SPQ
Length (mm) Width (mm) Height (mm)
ADS1283AIRHFR
ADS1283AIRHFT
ADS1283BIRHFR
ADS1283BIRHFT
ADS1283IRHFR
ADS1283IRHFT
VQFN
VQFN
VQFN
VQFN
VQFN
VQFN
RHF
RHF
RHF
RHF
RHF
RHF
24
24
24
24
24
24
3000
250
346.0
210.0
346.0
210.0
346.0
210.0
346.0
185.0
346.0
185.0
346.0
185.0
33.0
35.0
33.0
35.0
33.0
35.0
3000
250
3000
250
Pack Materials-Page 2
PACKAGE OUTLINE
RHF0024A
VQFN - 1 mm max height
S
C
A
L
E
3
.
0
0
0
PLASTIC QUAD FLATPACK - NO LEAD
4.1
3.9
A
B
PIN 1 INDEX AREA
0.5
0.3
5.1
4.9
0.30
0.18
DETAIL
OPTIONAL TERMINAL
TYPICAL
C
1 MAX
SEATING PLANE
0.08 C
0.05
0.00
2.65 0.1
2X 2
(0.1) TYP
12
EXPOSED
8
THERMAL PAD
20X 0.5
7
13
3.65 0.1
2X
3
25
SYMM
SEE TERMINAL
DETAIL
19
1
0.30
0.18
24X
0.1
C B A
PIN 1 ID
(OPTIONAL)
24
20
SYMM
0.05
0.5
0.3
24X
4219064 /A 04/2017
NOTES:
1. All linear dimensions are in millimeters. Any dimensions in parenthesis are for reference only. Dimensioning and tolerancing
per ASME Y14.5M.
2. This drawing is subject to change without notice.
3. The package thermal pad must be soldered to the printed circuit board for thermal and mechanical performance.
www.ti.com
EXAMPLE BOARD LAYOUT
RHF0024A
VQFN - 1 mm max height
PLASTIC QUAD FLATPACK - NO LEAD
(2.65)
SYMM
20
24
24X (0.6)
1
19
24X (0.24)
(3.65)
(1.575)
20X (0.5)
25
SYMM
(4.8)
(0.62)
TYP
(R0.05)
TYP
13
7
(
0.2) TYP
VIA
8
12
(1.025)
TYP
(3.8)
LAND PATTERN EXAMPLE
EXPOSED METAL SHOWN
SCALE:18X
0.07 MIN
ALL AROUND
0.07 MAX
ALL AROUND
SOLDER MASK
OPENING
METAL
EXPOSED
METAL
SOLDER MASK
OPENING
METAL UNDER
SOLDER MASK
EXPOSED
METAL
NON SOLDER MASK
DEFINED
SOLDER MASK
DEFINED
(PREFERRED)
SOLDER MASK DETAILS
4219064 /A 04/2017
NOTES: (continued)
4. This package is designed to be soldered to a thermal pad on the board. For more information, see Texas Instruments literature
number SLUA271 (www.ti.com/lit/slua271).
5. Vias are optional depending on application, refer to device data sheet. If any vias are implemented, refer to their locations shown
on this view. It is recommended that vias under paste be filled, plugged or tented.
www.ti.com
EXAMPLE STENCIL DESIGN
RHF0024A
VQFN - 1 mm max height
PLASTIC QUAD FLATPACK - NO LEAD
6X (1.17)
(0.685) TYP
20
24
24X (0.6)
1
19
24X (0.24)
(1.24)
TYP
20X (0.5)
SYMM
(4.8)
25
6X (1.04)
13
(R0.05) TYP
7
METAL
TYP
12
8
SYMM
(3.8)
SOLDER PASTE EXAMPLE
BASED ON 0.125 mm THICK STENCIL
EXPOSED PAD 25
75% PRINTED SOLDER COVERAGE BY AREA UNDER PACKAGE
SCALE:20X
4219064 /A 04/2017
NOTES: (continued)
6. Laser cutting apertures with trapezoidal walls and rounded corners may offer better paste release. IPC-7525 may have alternate
design recommendations.
www.ti.com
重要声明和免责声明
TI“按原样”提供技术和可靠性数据(包括数据表)、设计资源(包括参考设计)、应用或其他设计建议、网络工具、安全信息和其他资源,
不保证没有瑕疵且不做出任何明示或暗示的担保,包括但不限于对适销性、某特定用途方面的适用性或不侵犯任何第三方知识产权的暗示担
保。
这些资源可供使用 TI 产品进行设计的熟练开发人员使用。您将自行承担以下全部责任:(1) 针对您的应用选择合适的 TI 产品,(2) 设计、验
证并测试您的应用,(3) 确保您的应用满足相应标准以及任何其他功能安全、信息安全、监管或其他要求。
这些资源如有变更,恕不另行通知。TI 授权您仅可将这些资源用于研发本资源所述的 TI 产品的应用。严禁对这些资源进行其他复制或展示。
您无权使用任何其他 TI 知识产权或任何第三方知识产权。您应全额赔偿因在这些资源的使用中对 TI 及其代表造成的任何索赔、损害、成
本、损失和债务,TI 对此概不负责。
TI 提供的产品受 TI 的销售条款或 ti.com 上其他适用条款/TI 产品随附的其他适用条款的约束。TI 提供这些资源并不会扩展或以其他方式更改
TI 针对 TI 产品发布的适用的担保或担保免责声明。
TI 反对并拒绝您可能提出的任何其他或不同的条款。IMPORTANT NOTICE
邮寄地址:Texas Instruments, Post Office Box 655303, Dallas, Texas 75265
Copyright © 2023,德州仪器 (TI) 公司
相关型号:
©2020 ICPDF网 联系我们和版权申明