SP8527BS_技术文档

®

SP8527

Micropower Sampling 10-Bit A/D Converter

■ Low Cost

■ 10-Bit Serial Sampling ADC

■ Guaranteed +1.0 LSB Max INL

■ 8-Pin NSOIC Plastic Package

■ Low Power @ 230µA including

Automatic Shutdown: 1nA (typ)

■ Full differential input stage

■ Single Supply 3.0V to 5.5V operation

■ Digital Serial Interface

■ Sample Rate: 26.1µS

DESCRIPTION

The SP8527 is a very low power 10-Bit A/D converter. The SP8527 typically draws 230µA of

supply current when sampling at 38.3 kHz. Supply current drops linearly as the sample rate is

reduced. The ADC automatically powers down when not performing conversions, drawing only

leakage current. The SP8527 is available in 8-Pin NSOIC packages, specified over Commercial

and Industrial temperature ranges. The SP8527 is best suited for Battery-Operated Systems,

Portable Data Acquisition Instrumentation, Battery Monitoring, and Remote Sensing

applications. The serial port allows efficient data transfer to a wide range of microprocessors and

microcontrollers over 3 wires.

V

CC

GND

Internal

CC

REFL

V

10

REFL

DAC

VREF

Csample P

Csample N

+IN

-IN

PARALLEL TO

SERIAL SHIFT

REGISTER

INPUT

SWITCHES

SAR

COMPARATOR

Dout

CS/SHDN

SCLK

TIMING &

CONTROL LOGIC

SP8527 Block Diagram

SP8527DS/01

SP8527 Micropower Sampling 10-Bit A/D Converter

1

ABSOLUTE MAXIMUM RATINGS

These are stress ratings only and functional operation of the device at

these ratings or any other above those indicated in the operation

sections of the specifications below is not implied. Exposure to absolute

maximum rating conditions for extended periods of time may affect

reliability.

(TA=+25˚C unless otherwise noted) .....................................................

VCC to GND ................................................................................. 7.0V

Vin to GND .............................................................. -0.3 to VCC +0.3V

Digital input to GND ................................................ -0.3 to VCC +0.3V

Digital output to GND .............................................. -0.3 to VCC +0.3V

Operating Temperature Range

Commercial (J, K Version) ........................................... 0˚C to 70˚C

Industrial (A, B Version) .......................................... -40˚C to +85˚C

Lead Temperature (Solder 10Sec) ............................................ +300˚C

Storage Temperature .................................................. -65˚C to +150˚C

Power Dissipation to 70˚C ........................................................ 500mW

SPECIFICATIONS

Unless otherwise noted the following specifications apply for VCC=5V or 3.3V with limits applicable for Tmin to Tmax. Typical applies for Ta=25˚C.

VCC=5.0V

VCC=3.3V

PARAMETERS

MIN. TYP. MAX. MIN. TYP. MAX. UNITS CONDITIONS

DC ACCURACY

Resolution

10

Bits

Integral Linearity

K,B

+0.5 +1.0

LSB

Differential Linearity Error

K,B

+0.6 +2.0

+0.2 +2.0

+0.3 +2.0

+0.6 +2.0

+0.2 +2.0

+0.3 +3.0

LSB

Gain Error

K,B

Offset Error

K,B

ANALOG INPUT

Input Signal FS Range

Input Impedance

On Channel

0

V_ref

0

V_ref

20

100

3

20

100

3

pF

MΩ

pF

In Parallel with 100MΩ

Off Channel

100

.001

100

.001

MΩ

µA

Input Bias Current

Analog Input Range

1

-.05

V_CC+.05 -.05

V_CC+.05 Volts

CONVERSION SPEED

Sample Time

1.5

10

1.5

10

clock

cycles

clock

See Timing Diagrams

Conversion Time

cycles

Complete Cycle

Clock Period

Clock High Time

Clock Low Time

38.3

3.0

1.4

25.5

kHz

µS

See Timing Diagrams

2.0

.9

SP8527DS/01

SP8527 Micropower Sampling 10-Bit A/D Converter

2

SPECIFICATIONS (cont.)

Unless otherwise noted the following specifications apply for VCC=5V or 3.3V with limits applicable for Tmin to Tmax. Typical applies for Ta=25˚C.

VCC=5.0V

VCC=3.3V

PARAMETERS

MIN. TYP. MAX. MIN. TYP. MAX. UNITS CONDITIONS

DIGITAL INPUTS

Input Low Voltage, VIL

Input High Voltage, VIH

Input Current IIN

0.8

Volts

V_DD=5V ±5%

2.0

4.0

2.0

+2.0

+2.0 µA

Input Capacitance

3.0

pF

DIGITAL OUTPUTS

Data Format

Data Coding

VOH

See Timing Diagram

V_DD=5V +5%, IOH=-0.4mA

V_DD=5V +5%, IOL=+1.6mA

Volts

VOL

0.4

AC ACCURACY

Spurious free Dynamic

Range (SFDR)

70

68

dB

For all FFT’s

(Full Differential Mode)

If V_CC= 5V

fsample = 38.3kHz

fin = 15kHz

Total Harmonic Distortion (THD)

-70

60

-70

60

dB

Signal to Noise &

Distortion (SINAD)

If V_CC= 3.3V

fsample = 25.5kHz

fin = 12kHz

Signal to Noise (SNR)

61

2

61

3

dB

SAMPLING DYNAMICS

Acquisition Time to 0.05%

3

4.5

µs

-3dB Small Signal BW

Aperture Delay

4

20

3

30

MHz

nS

Aperture Jitter

Common-Mode Rejection Ratio 70

150

80

150

80

pS

dB

70

f_CM= 15kHz @ 5 volts

2.8kHz @ 3.3 volts

POWER SUPPLIES

Volts

V_CC

+3.0 +5.0 +5.5 +3.0 +3.3 +5.5

I_CC

Operation Mode

230 400

.001 0.5

80 300 µA

(CS=0) 38.3kHz, 5V conversion

rate. 25.5kHz 3.3 volts

Shutdown Mode

.001 0.5

µA

(CS=1)

Power Dissipation

Operating Mode

Shutdown Mode

1.15

.005 2.5

2

0.26 0.99 mW

.003 1.7

µW

TEMPERATURE RANGE

Commercial

Industrial

0˚ to +70˚C

-40˚ to +85˚C

-65˚ to +150˚C

0˚ to +70˚C

-40˚ to +85˚C

-65˚ to +150˚C ˚C

˚C

Storage

SP8527DS/01

SP8527 Micropower Sampling 10-Bit A/D Converter

3

SPECIFICATIONS (cont.)

Recommended Operating Conditions

VCC=5.0V

VCC=3.3V

SYMBOL

PARAMETERS

MIN. TYP. MAX. MIN. TYP. MAX.

UNITS

V_CC

Supply Voltage

+3.0

+5.0

+5.5

500

+3.0

+3.3

+5.5

333

Volts

f_CLK

t_CYC

Clock Frequency

Total Cycle Time

kHz

26.1

100

39.2

150

µS

t_suCS

Setup Time CSv

Before CLK^

nS

t_WHCLK

t_WLCLK

t_WHCS

CLK High Time

CLK Low Time

.9

1.4

150

µS

nS

CS High Time between 100

Data Transfers Cycles

t_SAMPLE

t_CONV

t_CLK

t_en

t_DIS

t_R

S/H Acquisition Time

ADC Conversion Time

2

SCLK Cycles

10

Clock Period

2.0

3.0

µS

nS

SCLK to D_OUTEnable

80

5

200

25

150

10

300

200

50

▼

CSN to D_OUTHi - Z

D_OUTRise Time

D_OUTFall Time

t_F

5

25

10

50

t_HDO

D_OUTValid After SCLK

80

200

150

300

▼

PIN ASSIGNMENTS

PIN DESCRIPTION

Pin 1- V_REF- Reference Voltage

Pin 2- +IN - Positive Input

Pin 3- -IN - Negative Input

Pin 4- GND - Ground

V

▼

1

2

3

4

8

7

6

5

REF

V

CC

+IN

SCLK

Pin 5- CS/SHDN - Chip Select Bar/Shutdown

Pin 6 - D_OUT- Data Out

-IN

D

OUT

GND

CS/SHDN

Pin 7- SCLK - Serial Clock

Pin 8- V_CC- Supply

SP8527DS/01

SP8527 Micropower Sampling 10-Bit A/D Converter

4

DESCRIPTION

The device features automatic shutdown and

will shutdown to a +0.5 µA power level as CS

is brought high (de-selected). Power is propor-

tional to conversion duty cycle and varies from

230 µA at 26.1 µS (Duty cycle = 100%) to

5.75 µA at 1.04 ms (Duty cycle = 2.5%).

The SP8527 is a 10 bit full differential

sampling ADC with a serial data interface. The

ADC samples and converts 10 bits of data in

26.1 µS with a 5V supply voltage applied. The

SP8527 will also operate at a 3.3V supply at

39.2 µS throughput. The device automatically

shuts down to a +0.5 µA (MAX) level as soon

as the chip is deselected (CS=1). Serial data

output is available in an MSB first format.

Examples:

Conversion rate I_CC@ 5V Duty Cycle

26.1 µS

52.2 µS

104 µS

1.04 mS

230 µA

115 µA

57.5 µA

5.75 µA

100%

50%

25%

FEATURES

2.5%

The input sampling scheme is full differential,

where the maximum full scale range is V . The

signal is applied between +IN and -I^RN^EF. The

signals applied at each input may both be

dynamic. This is in contrast with pseudo differ-

ential devices which must have input low held

at a constant level during conversion. The

converter will provide significant common mode

rejection because of the full differential

sampling. Each input independently must

remain between ground and Vcc to avoid

clamping the inputs. For proper conversion the

differential input (+IN - -IN) must be less than

or equal to Vref.

The device is configured such that it

delivers serial data MSB first requiring 13 clock

periods for a full conversion. Please refer to the

timing diagram.

Circuit Operation

The SP8527 is a SAR converter with full

differential sampled front end, capacitive DAC,

precision comparator, Successive Approxima-

tions Register, control logic and data output reg-

ister. After the input is sampled and held the

conversion process begins. The DAC MSB is

set and its output is compared with the signal

input, if the DAC output is less than the input,

the comparator outputs a one which is latched

into the SAR and simultaneously made

available at the ADC serial output pin. Each bit

is tested in a similar manner until the SAR

contains a code which represents the signal input

to within +1/2 LSB. During this process the SAR

content has been shifted out of the ADC serially.

The data appears at the DOUT pin MSB through

LSB in 13 clock periods. Note that the Chip

Select Bar pin must be toggled high between

conversions. The DOUT pin will be in a high

impedance state whenever Chip Select Bar is high.

After Chip Select Bar has been toggled and brought

low again, the converter begins a new conversion.

The device uses a capacitive DAC architecture

which provides the sampling behavior. This

results in full Nyquist performance at the

fastest throughput rate (38.3kHz) the device is

capable of.

The power supply voltage is variable from 3.0V

to 5.5V which provides supply flexibility.At the

5.0V supply level, conversion plus sampling

time is 26.1 µS and supply current is 230 µA

(1.15 mW). With a 3.3V supply the conversion

plus sampling time is 39.2 µS and current is

reduced to 80 µA (0.26 mW).

ADC TRANSFER FUNCTION

INPUT VOLTAGE

(+IN - -IN)

INPUT VOLTAGE

AT V_REF= 5V

OUTPUT

CODE

0 LSB

1 LSB

512 LSB

1022 LSB

1023 LSB

0V

0000000000

0000000001

1000000000

1111111110

1111111111

0.0049V

2.5000V

4.9902V

4.9951V

SP8527DS/01

SP8527 Micropower Sampling 10-Bit A/D Converter

5

referenced to the ground pin of the converter.

This prevents any voltage drops that occur in

the power supply's common return from appearing

in series with the input signal.

Single Ended or Full

Differential Operation

The SP8527 has a balanced full differential front

end. The SP8527 can be used in this manner, or

it can be used in single-ended circuits as well.

For single-ended systems, simply tie the -IN to

the Reference Low of the input signal, which is

allowed to range from 0V to V_CC. For a full

differential sampling configuration, both inputs

are sampled and held simultaneously. Because

of the balanced differential sampling, dynamic

common mode noise riding along the input

signal is cancelled above and beyond DC noise.

This is a significant improvement over psuedo-

differential sampling schemes, where the low

side of the input must remain constant during

the conversion, and therefore only DC noise (i.e.

signal offset) is cancelled. IfAC common mode

noise is left to be converted along with the

differental component, the output signal will be

degraded.

In full differential mode, the high and low side

board traces should run close to each other, with

the same layout. This will insure that any noise

coupling will be common mode, and cancelled

by the converters (patent pending) full differential

architecture.

If separate analog and digital ground planes are

not possible, care should be used to prevent

coupling between analog and digital signals. If

analog and digital lines must cross, they should

do so at right angles. Parallel analog and digital

lines should be separated by a circuit board trace

which is connected to common.

The reference pin on the SP8527 should be kept

as clean as possible. A noise signal of 4.88mV

(for VREF = 5.0V) will produce 1 lsb of error

in the output code. For convenience, the VREF

pin can be tied to the VCC pin, but now the same

care should be taken with the VCC pin as with

the VREF pin. Whether or not VCC is tied to

VREF, the VCC pin should always be bypassed

to the GROUND pin with a parallel combination

of a 6.8µF tantalum and a 0.1µF ceramic

capacitor. To maintain maximum system

accuracy, the supply connected to the VCC pin

should be well isolated from digital supplies and

wide load variations.Aseparate conductor from

the supply regulator to the A/D converter will

limit the effects of digital switching elsewhere

in the system. Power supply noise can degrade

the converters performance. Especially corrupting

are noise and spikes from a switching

power supply.

Full differential sampling allows flexibility in

converting the input signal. If the signal low- side

is already tied to a ground elsewhere in the

system, it can be hardwired to the low side

input (i.e., -IN) which acts as a signal ground

sense, breaking a potential ground loop. It is also

possible to drive the inputs balanced differential,

as long as both inputs are within the power rails.

In this configuration, both the high and low

signals have the same impedance looking back

to ground, and therefore pick up the same noise

along the physical path from signal source (i.e.,

sensor, transducer, battery) to the converter. This

noise becomes common mode, and is cancelled

out by the differential sampling of the SP8527.

Layout Considerations

To preserve the high resolution and linearity of

the SP8527 attention must be given to circuit

board layout, ground impedance and bypassing.

To avoid introducing distortion when driving the

A/D converter input, the input signal source

should be able to charge the SP8527's equivalent

20 pF of input capacitance from zero volts to

the signal level in 1.5 clock periods.

A circuit board layout which includes separate

analog and digital ground planes will prevent

the coupling of noise into sensitive converter

circuits and will help to preserve the dynamic

performance of the device. In single ended

mode, the analog input signal should be

SP8527DS/01

SP8527 Micropower Sampling 10-Bit A/D Converter

6

FIGURE 1. MSB FIRST TIMING

FIGURE 2. DETAILED TIMING

SP8527 Timing Diagram

SP8527DS/01

SP8527 Micropower Sampling 10-Bit A/D Converter

7

Icc vs. Sampling Rate

(Clock Rate = 333kHz)

Vcc = 3.3V

Icc vs. Sampling Rate

(Clock Rate = 500kHz)

Vcc = 5V

90.0

80.0

70.0

60.0

50.0

40.0

30.0

250.0

200.0

150.0

100.0

20.0

10.0

0.0

50.0

0.0

10

100

1000

10000

100000

10

100

1000

10000

100000

conversion time (µs)

Vcc = 5V

Vref = 5V

Vcc = 3.3V

Vref = 3.3V

+1

INLE

-1

+1

DNLE

-1

DNLE

-1

1023

512

0

1023

512

0

Input CMRR

Vcc = 5V

100

80

60

40

20

0

10.0E+0 100.0E+0 1.0E+3 10.0E+3 100.0E+3 1.0E+6

common mode frequency(Hz)

SP8527DS/01

SP8527 Micropower Sampling 10-Bit A/D Converter

8

For all plots, V_CC= 5V, Conversion Rate = 38.3kHz.

Icc vs. Temperature

Gain vs.Temperature

1.5

250

1.0

.05

240

230

220

210

200

0.00

-0.5

-1.0

-1.5

-50

-25

0

25

50

75

100

125

-50

-25

0

25

50

75

100

125

temperature (C)

Offset vs.Temperature

FFT 20 dB/div

1.5

1.0

.05

0

-0.5

-1.0

-1.5

0Hz

1.3kHz/div

SNR = 61.26 dB

THD = -70.7 dB

10.4kHz

SINAD = 60.79 dB

SFDR = 70.43 dB

Vinamp = -0.49 dB

Fund Freq = 9.885kHz

-50

-25

0

25

50

75

100

125

temperature (C)

Spurious Free Dynamic Range

SINAD

80

70

68

66

64

62

60

58

75

70

65

60

56

54

52

55

50

1000

10000

1000

10000

input frequency (Hz)

Signal to Noise Ratio

Total Harmonic Distortion

70

-50

-55

-60

68

66

64

62

60

58

56

54

52

-65

-70

-75

-80

50

1000

10000

1000

10000

input frequency (Hz)

SP8527DS/01

SP8527 Micropower Sampling 10-Bit A/D Converter

9

PACKAGE: PLASTIC

DUAL–IN–LINE

(NARROW)

E1

E

D1 = 0.005" min.

(0.127 min.)

A1 = 0.015" min.

(0.381min.)

D

A = 0.210" max.

(5.334 max).

C

A2

Ø

L

B1

B

e

= 0.300 BSC

(7.620 BSC)

e = 0.100 BSC

(2.540 BSC)

A

ALTERNATE

END PINS

(BOTH ENDS)

DIMENSIONS (Inches)

Minimum/Maximum

(mm)

8–PIN

14–PIN

16–PIN

18–PIN

20–PIN

22–PIN

0.115/0.195

(2.921/4.953)

0.115/0.195

(2.921/4.953)

0.115/0.195

(2.921/4.953)

A2

(2.921/4.953) (2.921/4.953) (2.921/4.953)

0.014/0.022

(0.356/0.559)

0.014/0.022

(0.356/0.559)

0.014/0.022

(0.356/0.559)

B

(0.356/0.559) (0.356/0.559) (0.356/0.559)

0.045/0.070 0.045/0.070 0.045/0.070

0.045/0.070

B1

C

(1.143/1.778) (1.143/1.778) (1.143/1.778)

(1.143/1.778)

0.008/0.014 0.008/0.014 0.008/0.014

0.008/0.014

(0.203/0.356)

0.008/0.014

(0.203/0.356)

0.008/0.014

(0.203/0.356)

(0.203/0.356) (0.203/0.356) (0.203/0.356)

0.355/0.400 0.735/0.775 0.780/0.800

0.880/0.920

0.980/1.060

1.145/1.155

D

(9.017/10.160) (18.669/19.685) (19.812/20.320) (22.352/23.368) (24.892/26.924) (29.083/29.337)

0.300/0.325

(7.620/8.255)

0.300/0.325

(7.620/8.255)

0.300/0.325

(7.620/8.255)

E

(7.620/8.255) (7.620/8.255) (7.620/8.255)

0.240/0.280 0.240/0.280 0.240/0.280

0.240/0.280

E1

L

(6.096/7.112) (6.096/7.112) (6.096/7.112)

(6.096/7.112)

0.115/0.150 0.115/0.150 0.115/0.150

(2.921/3.810) (2.921/3.810) (2.921/3.810)

0.115/0.150

(2.921/3.810)

0.115/0.150

(2.921/3.810)

0.115/0.150

(2.921/3.810)

0°/ 15°

(0°/15°)

0°/ 15°

(0°/15°)

0°/ 15°

(0°/15°)

0°/ 15°

(0°/15°)

0°/ 15°

(0°/15°)

0°/ 15°

(0°/15°)

Ø

SP8527DS/01

SP8527 Micropower Sampling 10-Bit A/D Converter

10

PACKAGE: PLASTIC

SMALL OUTLINE (SOIC)

(NARROW)

E

H

h x 45°

D

A

Ø

A1

L

e

B

DIMENSIONS (Inches)

Minimum/Maximum

(mm)

8–PIN

14–PIN

0.053/0.069

16–PIN

A

A1

B

D

E

0.053/0.069

(1.346/1.748) (1.346/1.748) (1.346/1.748)

0.053/0.069

0.004/0.010

(0.102/0.249

0.004/0.010

(0.102/0.249) (0.102/0.249)

0.004/0.010

0.014/0.019

(0.35/0.49)

0.013/0.020

(0.330/0.508) (0.330/0.508)

0.013/0.020

0.189/0.197

(4.80/5.00)

0.337/0.344 0.386/0.394

(8.552/8.748) (9.802/10.000)

0.150/0.157 0.150/0.157

0.150/0.157

(3.802/3.988) (3.802/3.988) (3.802/3.988)

e

0.050 BSC

(1.270 BSC)

0.050 BSC

(1.270 BSC)

0.050 BSC

(1.270 BSC)

H

h

0.228/0.244

(5.801/6.198) (5.801/6.198) (5.801/6.198)

0.010/0.020

(0.254/0.498) (0.254/0.498) (0.254/0.498)

0.010/0.020

L

0.016/0.050 0.016/0.050 0.016/0.050

(0.406/1.270) (0.406/1.270) (0.406/1.270)

Ø

0°/8°

(0°/8°)

0°/8°

(0°/8°)

0°/8°

(0°/8°)

SP8527DS/01

SP8527 Micropower Sampling 10-Bit A/D Converter

11

ORDERING INFORMATION

Model ........................................................ Linearity (LSB) ..................... Temperature Range ...............................................................Package

SP8527BN .......................................................... ±1.0 .................................... –40˚C to +85˚C .............................................. 8-pin, 0.3" Plastic DIP

SP8527KN .......................................................... ±1.0 ..................................... –0˚C to +70˚C ............................................... 8-pin, 0.3" Plastic DIP

SP8527BS .......................................................... ±1.0 .................................... –40˚C to +85˚C ......................................... 8-pin, 0.15" Plastic SOIC

SP8527KS .......................................................... ±1.0 ..................................... –0˚C to +70˚C .......................................... 8-pin, 0.15" Plastic SOIC

Please consult the factory for pricing and availability on a Tape-On-Reel option.

Co rp o ra tio n

SIGNAL PROCESSING EXCELLENCE

Sipex Corporation

Headquarters and

Sales Office

22 Linnell Circle

Billerica, MA 01821

TEL: (978) 667-8700

FAX: (978) 670-9001

e-mail: sales@sipex.com

Sales Office

233 South Hillview Drive

Milpitas, CA 95035

TEL: (408) 934-7500

FAX: (408) 935-7600

Sipex Corporation reserves the right to make changes to any products described herein. Sipex does not assume any liability arising out of the

application or use of any product or circuit described hereing; neither does it convey any license under its patent rights nor the rights of others.

SP8527DS/01

SP8527 Micropower Sampling 10-Bit A/D Converter

12


型号：	SP8527BS
厂家：	SIPEX CORPORATION
描述：	Micropower Sampling 10-Bit A/D Converter 微功耗采样10位A / D转换器转换器
文件：	总12页 (文件大小：183K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

SP8527BS [SIPEX]

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SP8527KN

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