MAX1181ECM [MAXIM]
Dual 10-Bit, 80Msps, 3V, Low-Power ADC with Internal Reference and Parallel Outputs; 双路10位，80Msps ， 3V ，低功耗ADC，内置电压基准及并行输出
| 型号： | MAX1181ECM |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Dual 10-Bit, 80Msps, 3V, Low-Power ADC with Internal Reference and Parallel Outputs |
| 文件： | 总20页 (文件大小：304K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-2093; Rev 1; 2/07
Dual 10-Bit, 80Msps, 3V, Low-Power ADC
with Internal Reference and Parallel Outputs
General Description
Features
♦ Single 3V Operation
The MAX1181 is a 3V, dual 10-bit, analog-to-digital
converter (ADC) featuring fully-differential wideband
track-and-hold (T/H) inputs, driving two pipelined, nine-
stage ADCs. The MAX1181 is optimized for low-power,
high-dynamic performance applications in imaging,
instrumentation, and digital communication applica-
tions. The MAX1181 operates from a single 2.7V to 3.6V
supply, consuming only 246mW, while delivering a typi-
cal signal-to-noise ratio (SNR) of 59dB at an input fre-
quency of 20MHz and a sampling rate of 80Msps. The
T/H driven input stages incorporate 400MHz (-3dB)
input amplifiers. The converters may also be operated
with single-ended inputs. In addition to low operating
power, the MAX1181 features a 2.8mA sleep mode, as
well as a 1µA power-down mode to conserve power
during idle periods.
♦ Excellent Dynamic Performance
59dB SNR at f = 20MHz
IN
73dB SFDR at f = 20MHz
IN
♦ Low Power
82mA (Normal Operation)
2.8mA (Sleep Mode)
1µA (Shutdown Mode)
♦ 0.02dB Gain and 0.25° Phase Matching (typ)
♦ Wide 1V
Differential Analog Input Voltage
P-P
Range
♦ 400MHz, -3dB Input Bandwidth
♦ On-Chip 2.048V Precision Bandgap Reference
♦ User-Selectable Output Format—Two’s
Complement or Offset Binary
An internal 2.048V precision bandgap reference sets
the full-scale range of the ADC. A flexible reference
structure allows the use of the internal or external
reference, if desired for applications requiring
increased accuracy or a different input voltage range.
♦ 48-Pin TQFP Package with Exposed Pad for
Improved Thermal Dissipation
♦ Evaluation Kit Available
Ordering Information
The MAX1181 features parallel, CMOS-compatible
three-state outputs. The digital output format is set to
two’s complement or straight offset binary through a
single control pin. The device provides for a separate
output power supply of 1.7V to 3.6V for flexible interfac-
ing. The MAX1181 is available in a 7mm ✕ 7mm, 48-pin
TQFP package, and is specified for the extended
industrial (-40°C to +85°C) temperature range.
PART
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
48 TQFP-EP*
48 TQFP-EP*
MAX1181ECM
MAX1181ECM+
*EP = Exposed paddle.
+Denotes a lead-free package.
Pin Configuration
Pin-compatible higher and lower speed versions of the
MAX1181 are also available. Please refer to the
MAX1180 datasheet for 105Msps, the MAX1182
datasheet for 65Msps, the MAX1183 datasheet for
40Msps, and the MAX1184 datasheet for 20Msps. In
addition to these speed grades, this family includes a
20Msps multiplexed output version (MAX1185), for
which digital data is presented time-interleaved on a
single, parallel 10-bit output port.
COM
1
2
36 D1A
35 D0A
34 OGND
V
DD
GND
INA+
INA-
3
4
33 OV
32 OV
DD
DD
5
V
6
31 OGND
30 D0B
29 D1B
28 D2B
DD
MAX1181
Applications
High-Resolution Imaging
I/Q Channel Digitization
GND
INB-
INB+
GND
7
8
9
D3B
D4B
D5B
10
11
12
27
26
25
EP*
V
DD
Multichannel IF Undersampling
Instrumentation
CLK
Video Application
48 TQFP-EP
NOTE: THE PIN 1 INDICATOR FOR LEAD-FREE PACKAGES IS REPLACED
Functional Diagram appears at end of data sheet.
BY A "+" SIGN.
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim's website at www.maxim-ic.com.
Dual 10-Bit, 80Msps, 3V, Low-Power ADC
with Internal Reference and Parallel Outputs
ABSOLUTE MAXIMUM RATINGS
V
, OV
to GND ...............................................-0.3V to +3.6V
Continuous Power Dissipation (T = +70°C)
A
DD
DD
OGND to GND.......................................................-0.3V to +0.3V
48-Pin TQFP-EP (derate 30.4mW/°C above +70°C)...2430mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-60°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
INA+, INA-, INB+, INB- to GND ...............................-0.3V to V
REFIN, REFOUT, REFP, REFN, CLK,
DD
COM to GND ...........................................-0.3V to (V + 0.3V)
DD
OE, PD, SLEEP, T/B, D9A–D0A,
D9B–D0B to OGND ..............................-0.3V to (OV + 0.3V)
DD
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
= 3V, OV
= 2.5V; 0.1µF and 1.0µF capacitors from REFP, REFN, and COM to GND; REFOUT connected to REFIN through a
DD
DD
IN
10kΩ resistor, V = 2V
(differential with respect to COM), C = 10pF at digital outputs (Note 1), f
= 83.333MHz, T = T
to
MIN
P-P
L
CLK
A
T
MAX
, unless otherwise noted. Typical values are at T = +25°C.) (Note 2)
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DC ACCURACY
Resolution
10
-2
Bits
LSB
Integral Nonlinearity
Differential Nonlinearity
Offset Error
INL
f
f
= 7.47MHz
0.6
0.4
2.2
1.0
+2
2
IN
DNL
= 7.47MHz, no missing codes guaranteed
LSB
IN
% FS
% FS
Gain Error
0
ANALOG INPUT
Differential Input Voltage Range
V
Differential or single-ended inputs
Switched capacitor load
1.0
V
V
DIFF
Common-Mode Input Voltage
Range
V
/2
DD
0.5
V
CM
Input Resistance
R
25
5
kΩ
IN
IN
Input Capacitance
C
pF
CONVERSION RATE
Maximum Clock Frequency
f
80
MHz
CLK
Clock
Cycles
Data Latency
5
DYNAMIC CHARACTERISTICS
f
f
f
f
f
f
f
f
= 7.47MHz, T = +25°C
56.5
56
59.5
59
59
INA or B
INA or B
INA or B
INA or B
INA or B
INA or B
INA or B
INA or B
A
Signal-to-Noise Ratio
(Note 3)
SNR
SINAD
SFDR
dB
dB
= 20MHz, T = +25°C
A
= 39.9MHz
= 7.47MHz, T = +25°C
56
55.3
59
A
Signal-to-Noise And Distortion
(Note 3)
= 20MHz, T = +25°C
58.5
58.5
75
73
71
A
= 39.9MHz
= 7.47MHz, T = +25°C
65
64
A
Spurious-Free Dynamic
Range (Note 3)
= 20MHz, T = +25°C
dBc
A
= 39.9MHz
= 7.47MHz
fINA or B
f
f
f
-76
INA or B
INA or B
INA or B
Third-Harmonic Distortion
(Note 3)
HD3
dBc
= 20MHz
-76
-75
= 39.9MHz
2
_______________________________________________________________________________________
Dual 10-Bit, 80Msps, 3V, Low-Power ADC
with Internal Reference and Parallel Outputs
ELECTRICAL CHARACTERISTICS (continued)
(V
= 3V, OV
= 2.5V; 0.1µF and 1.0µF capacitors from REFP, REFN, and COM to GND; REFOUT connected to REFIN through a
DD
DD
IN
10kΩ resistor, V = 2V
(differential with respect to COM), C = 10pF at digital outputs (Note 1), f
= 83.333MHz, T = T
to
MIN
P-P
L
CLK
A
T
MAX
, unless otherwise noted. Typical values are at T = +25°C.) (Note 2)
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
-73
-70
-70
MAX
-64
UNITS
f
f
f
= 7.47MHz, T = +25°C
INA or B
INA or B
INA or B
A
Total Harmonic Distortion
(First Four Harmonics) (Note 3)
= 20MHz, T = +25°C
-63
THD
dBc
A
= 39.9MHz
Intermodulation Distortion
(First Five Odd-Order IMDs)
f
f
= 38.1546MHz at -6.5dBFS
= 41.9532MHz at -6.5dBFS
INA or B
INA or B
IMD
-73.5
dBc
(Note 4)
Small-Signal Bandwidth
Full-Power Bandwidth
Aperture Delay
Input at -20dBFS, differential inputs
Input at -0.5dBFS, differential inputs
500
400
1
MHz
MHz
ns
FPBW
t
AD
Aperture Jitter
t
2
ps
RMS
AJ
Overdrive Recovery Time
Differential Gain
For 1.5 x full-scale input
2
ns
%
1
Differential Phase
Output Noise
0.25
0.2
degrees
LSB
INA+ = INA- = INB+ = INB- = COM
RMS
INTERNAL REFERENCE
2.048
3%
Reference Output Voltage
REFOUT
TC
V
Reference Temperature
Coefficient
60
ppm/°C
REF
Load Regulation
1.25
mV/mA
BUFFERED EXTERNAL REFERENCE (V
= 2.048V)
REFIN
REFIN Input Voltage
V
2.048
2.012
V
V
REFIN
Positive Reference Output
Voltage
V
REFP
Negative Reference Output
Voltage
V
0.988
V
REFN
Differential Reference Output
Voltage Range
ΔV
ΔV
= V
- V
REFN
0.95
1.024
> 50
> 5
1.10
V
REF
REF
REFP
REFIN Resistance
R
REFIN
MΩ
mA
Maximum REFP, COM Source
Current
I
I
SOURCE
Maximum REFP, COM Sink
Current
I
250
µA
SINK
Maximum REFN Source Current
Maximum REFN Sink Current
250
> 5
µA
SOURCE
I
mA
SINK
UNBUFFERED EXTERNAL REFERENCE (V
= AGND, reference voltage applied to REFP, REFN and COM )
REFIN
R
R
Measured between REFP and COM and
REFN and COM
REFP,
REFP, REFN Input Resistance
4
kΩ
REFN
_______________________________________________________________________________________
3
Dual 10-Bit, 80Msps, 3V, Low-Power ADC
with Internal Reference and Parallel Outputs
ELECTRICAL CHARACTERISTICS (continued)
(V
= 3V, OV
= 2.5V; 0.1µF and 1.0µF capacitors from REFP, REFN, and COM to GND; REFOUT connected to REFIN through a
DD
DD
IN
10kΩ resistor, V = 2V
(differential with respect to COM), C = 10pF at digital outputs (Note 1), f
= 83.333MHz, T = T
to
MIN
P-P
L
CLK
A
T
MAX
, unless otherwise noted. Typical values are at T = +25°C.) (Note 2)
A
PARAMETER
SYMBOL
CONDITIONS
- V
MIN
TYP
MAX UNITS
Differential Reference Input
Voltage
1.024
10%
ΔV
ΔV
= V
V
REF
COM
REFP
REFN
REF
REFP
REFN
V
/ 2
DD
COM Input Voltage
REFP Input Voltage
REFN Input Voltage
V
V
V
V
V
10%
V
COM
+ ΔV
/ 2
/ 2
REF
V
COM
V
- ΔV
REF
DIGITAL INPUTS (CLK, PD, OE, SLEEP, T/B)
0.8 x
CLK
V
DD
Input High Threshold
Input Low Threshold
V
V
IH
0.8 x
OV
PD, OE, SLEEP, T/B
CLK
DD
0.2 x
V
DD
V
V
IL
0.2 x
OV
PD, OE, SLEEP, T/B
DD
Input Hysteresis
Input Leakage
V
0.1
5
V
HYST
I
IH
V
V
= OV or V (CLK)
5
5
IH
IL
DD
DD
µA
pF
I
= 0
IL
Input Capacitance
C
IN
DIGITAL OUTPUTS (D9A–D0A, D9B–D0B)
Output-Voltage Low
V
I
I
= 200µA
0.2
10
V
V
OL
SINK
OV
- 0.2
DD
Output-Voltage High
V
= 200µA
SOURCE
OH
Three-State Leakage Current
Three-State Output Capacitance
POWER REQUIREMENTS
Analog Supply Voltage Range
Output Supply Voltage Range
I
OE = OV
OE = OV
µA
pF
LEAK
DD
C
5
OUT
DD
V
2.7
1.7
3.0
2.5
82
2.8
1
3.6
3.6
97
V
V
DD
OV
DD
Operating, f
Sleep mode
= 20MHz at -0.5dBFS
INA or B
mA
Analog Supply Current
Output Supply Current
Power Dissipation
I
VDD
Shutdown, clock idle, PD = OE = OV
15
µA
DD
Operating, C = 15pF , f
L
-0.5dBFS
= 20MHz at
INA or B
13
mA
I
OVDD
Sleep mode
100
2
µA
mW
µW
Shutdown, clock idle, PD = OE = OV
10
DD
Operating, f
Sleep mode
= 20MHz at -0.5dBFS
246
8.4
3
291
INA or B
PDISS
Shutdown, clock idle, PD = OE = OV
45
DD
4
_______________________________________________________________________________________
Dual 10-Bit, 80Msps, 3V, Low-Power ADC
with Internal Reference and Parallel Outputs
ELECTRICAL CHARACTERISTICS (continued)
(V
= 3V, OV
= 2.5V; 0.1µF and 1.0µF capacitors from REFP, REFN, and COM to GND; REFOUT connected to REFIN through a
DD
DD
IN
10kΩ resistor, V = 2V
(differential with respect to COM), C = 10pF at digital outputs (Note 1), f
= 83.333MHz, T = T
to
MIN
P-P
L
CLK
A
T
MAX
, unless otherwise noted. Typical values are at T = +25°C.) (Note 2)
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
0.2
MAX UNITS
mV/V
Offset
Gain
Power Supply Rejection
PSRR
0.1
%/V
TIMING CHARACTERISTICS
CLK Rise to Output Data Valid
Output Enable Time
t
Figure 3 (Note 5)
5
8
ns
ns
ns
ns
ns
DO
t
Figure 4
10
1.5
ENABLE
Output Disable Time
t
Figure 4
DISABLE
CLK Pulse-Width High
CLK Pulse-Width Low
t
Figure 3 clock period: 12ns
Figure 3 clock period: 12ns
Wakeup from sleep mode
Wakeup from shutdown
6
6
1
CH
t
1
CL
0.28
1.5
Wake-Up Time (Note 6)
t
µs
WAKE
CHANNEL-TO-CHANNEL MATCHING
Crosstalk
f
f
f
= 20MHz at -0.5dBFS
= 20MHz at -0.5dBFS
= 20MHz at -0.5dBFS
-70
dB
dB
INA or B
INA or B
INA or B
Gain Matching
0.02
0.25
0.2
Phase Matching
degrees
Note 1: Equivalent dynamic performance is obtainable over full OV
range with reduced C .
L
DD
Note 2: Specifications at ≥ +25°C are guaranteed by production test and < +25°C are guaranteed by design and characterization.
Note 3: SNR, SINAD, THD, SFDR, and HD3 are based on an analog input voltage of -0.5dBFS, referenced to a +1.024V full-scale
input voltage range.
Note 4: Intermodulation distortion is the total power of the intermodulation products relative to the individual carrier. This number is
6dB or better, if referenced to the two-tone envelope.
Note 5: Digital outputs settle to V , V . Parameter guaranteed by design.
IH IL
Note 6: With REFIN driven externally, REFP, COM, and REFN are left floating while powered down.
Typical Operating Characteristics
(V
= 3V, OV
= 2.5V, internal reference, differential input at -0.5dBFS, f
= 80.0006MHz, C ≈ 10pF. T = +25°C, unless other-
DD
DD
CLK L A
wise noted.)
FFT PLOT CHA (8192-POINT RECORD,
DIFFERENTIAL INPUT)
FFT PLOT CHB (8192-POINT RECORD,
DIFFERENTIAL INPUT)
FFT PLOT CHA (8192-POINT RECORD,
DIFFERENTIAL INPUT)
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
0
f
f
f
= 19.9123MHz
= 24.9123MHz
= 80.0006MHz
CHA
INA
INB
CLK
f
f
f
= 6.0449MHz
= 7.5099MHz
= 80.0006MHz
f
f
f
= 6.0449MHz
= 7.5099MHz
= 80.0006MHz
CHB
INA
INB
CLK
INA
INB
CLK
-10 CHA
-20
A
INA
= -0.52dBFS
A
INA
= -0.46dBFS
A
INB
= -0.52dBFS
-30
-40
-50
-60
-70
-80
-90
-100
0
5
10 15 20 25 30 35 40
ANALOG INPUT FREQUENCY (MHz)
0
5
10 15 20 25 30 35 40
ANALOG INPUT FREQUENCY (MHz)
0
5
10 15 20 25 30 35 40
ANALOG INPUT FREQUENCY (MHz)
_______________________________________________________________________________________
5
Dual 10-Bit, 80Msps, 3V, Low-Power ADC
with Internal Reference and Parallel Outputs
Typical Operating Characteristics (continued)
(V
= 3V, OV
= 2.5V, internal reference, differential input at -0.5dBFS, f
= 80.0006MHz, C ≈ 10pF. T = +25°C, unless other-
DD
DD
CLK
L
A
wise noted.)
FFT PLOT CHB (8192-POINT RECORD,
DIFFERENTIAL INPUT)
FFT PLOT CHA (8192-POINT RECORD,
DIFFERENTIAL INPUT)
FFT PLOT CHB (8192-POINT RECORD,
DIFFERENTIAL INPUT)
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
CHB
f
f
f
= 40.4202MHz
= 47.0413MHz
= 80.0006MHz
= -0.52dBFS
f
f
f
= 19.9123MHz
= 24.9123MHz
= 80.0006MHz
= -0.53dBFS
f
f
f
= 40.4202MHz
= 47.0413MHz
= 80.0006MHz
= -0.53dBFS
INA
INB
CLK
INA
INB
CLK
INA
INB
CLK
CHB
CHA
A
A
A
INA
INB
INB
0
5
10 15 20 25 30 35 40
ANALOG INPUT FREQUENCY (MHz)
0
5
10 15 20 25 30 35 40
ANALOG INPUT FREQUENCY (MHz)
0
5
10 15 20 25 30 35 40
ANALOG INPUT FREQUENCY (MHz)
TWO-TONE IMD PLOT (8192-POINT RECORD,
SIGNAL-TO-NOISE RATIO
vs. ANALOG INPUT FREQUENCY
SIGNAL-TO-NOISE AND DISTORTION
vs. ANALOG INPUT FREQUENCY
COHERENT SAMPLING)
0
61
60
59
58
57
56
55
61
60
59
58
57
56
55
f
f
f
= 38.1546MHz
= 41.9632MHz
= 80.0006MHz
f
IN1
IN2
CLK
IN1
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
CHA
CHA
A
= A = -6dBFS
IN2
IN1
f
IN2
CHB
CHB
2nd ORDER IMD
0
5
10 15 20 25 30 35 40
ANALOG INPUT FREQUENCY (MHz)
0
10 20 30 40 50 60 70 80 90 100
ANALOG INPUT FREQUENCY (MHz)
0
10 20 30 40 50 60 70 80 90 100
ANALOG INPUT FREQUENCY (MHz)
FULL-POWER INPUT BANDWIDTH
vs. ANALOG INPUT FREQUENCY
(SINGLE-ENDED)
TOTAL HARMONIC DISTORTION
vs. ANALOG INPUT FREQUENCY
SPURIOUS-FREE DYNAMIC RANGE
vs. ANALOG INPUT FREQUENCY
-65
-68
-71
-74
-77
-80
6
4
80
77
74
71
68
65
CHA
CHB
2
0
CHA
-2
CHB
-4
-6
-8
0
10 20 30 40 50 60 70 80 90 100
ANALOG INPUT FREQUENCY (MHz)
1
10
100
1000
0
10 20 30 40 50 60 70 80 90 100
ANALOG INPUT FREQUENCY (MHz)
ANALOG INPUT FREQUENCY (MHz)
6
_______________________________________________________________________________________
Dual 10-Bit, 80Msps, 3V, Low-Power ADC
with Internal Reference and Parallel Outputs
Typical Operating Characteristics (continued)
(V
= 3V, OV
= 2.5V, internal reference, differential input at -0.5dBFS, f
= 80.0006MHz, C ≈ 10pF. T = +25°C, unless other-
DD
DD
CLK
L
A
wise noted.)
SMALL-SIGNAL INPUT BANDWIDTH
vs. ANALOG INPUT FREQUENCY
(SINGLE-ENDED)
SIGNAL-TO-NOISE RATIO
SIGNAL-TO-NOISE AND DISTORTION
vs. ANALOG INPUT POWER (f = 20MHz)
IN
vs. ANALOG INPUT POWER (f = 20MHz)
IN
6
4
65
60
55
50
45
60
58
56
54
52
50
V
= 100mV
P-P
IN
2
0
-2
-4
-6
-8
-9 -8 -7 -6 -5 -4 -3 -2 -1
ANALOG INPUT POWER (dBFS)
0
-9 -8 -7 -6 -5 -4 -3 -2 -1
ANALOG INPUT POWER (dBFS)
0
1
10
100
1000
ANALOG INPUT FREQUENCY (MHz)
TOTAL HARMONIC DISTORTION vs. ANALOG
SPURIOUS-FREE DYNAMIC RANGE vs. ANALOG
INTEGRAL NONLINEARITY
(BEST-STRAIGHT-LINE FIT)
INPUT POWER (f = 20MHz)
INPUT POWER (f = 20MHz)
IN
IN
-40
100
1.0
0.8
-45
-50
-55
95
90
85
0.6
0.4
-60
-65
80
75
0.2
0
-70
-75
-80
-85
-90
70
65
60
55
50
-0.2
-0.4
-0.6
-0.8
-1.0
-95
-100
45
40
-9 -8 -7 -6 -5 -4 -3 -2 -1
ANALOG INPUT POWER (dBFS)
0
-9 -8 -7 -6 -5 -4 -3 -2 -1
ANALOG INPUT POWER (dBFS)
0
0
128 256 384 512 640 768 896 1024
DIGITAL OUTPUT CODE
GAIN ERROR vs. TEMPERATURE,
OFFSET ERROR vs. TEMPERATURE,
EXTERNAL REFERENCE (V
= 2.048V)
EXTERNAL REFERENCE (V
= 2.048V)
DIFFERENTIAL NONLINEARITY
REFIN
REFIN
1.0
0.8
4
5
3
CHB
3
2
1
0
0.6
CHB
0.4
0.2
1
0
-0.2
-0.4
-0.6
-0.8
-1.0
-1
-3
-5
CHA
CHA
-1
-2
0
128 256 384 512 640 768 896 1024
DIGITAL OUTPUT CODE
-40
-15
10
35
60
85
-40
-15
10
35
60
85
TEMPERATURE (°C)
TEMPERATURE (°C)
_______________________________________________________________________________________
7
Dual 10-Bit, 80Msps, 3V, Low-Power ADC
with Internal Reference and Parallel Outputs
Typical Operating Characteristics (continued)
(V
= 3V, OV
= 2.5V, internal reference, differential input at -0.5dBFS, f
= 80.0006MHz, C ≈ 10pF. T = +25°C, unless other-
DD
DD
CLK
L
A
wise noted.)
ANALOG POWER-DOWN CURRENT
vs. ANALOG POWER SUPPLY
ANALOG SUPPLY CURRENT
vs. ANALOG SUPPLY VOLTAGE
ANALOG SUPPLY CURRENT vs. TEMPERATURE
2.0
1.6
1.2
0.8
0.4
0
100
100
90
80
70
60
50
OE = PD = OV
DD
90
80
70
60
50
2.70 2.85 3.00 3.15 3.30 3.45 3.60
(V)
-40
-15
10
35
60
85
2.70 2.85 3.00 3.15 3.30 3.45 3.60
V
DD
TEMPERATURE (°C)
V
(V)
DD
SNR/SINAD, -THD/SFDR
vs. CLOCK DUTY CYCLE
INTERNAL REFERENCE VOLTAGE
vs. ANALOG SUPPLY VOLTAGE
80
75
70
65
60
55
50
2.075
f
= 24.9123MHz
INA
SFDR
2.065
2.055
2.045
2.035
2.025
-THD
SNR
SINAD
55
35
40
45
50
60
65
2.70 2.85 3.00 3.15 3.30 3.45 3.60
CLOCK DUTY CYCLE (%)
V
(V)
DD
INTERNAL REFERENCE VOLTAGE
vs. TEMPERATURE
OUTPUT NOISE HISTOGRAM (DC INPUT)
140000
120000
100000
80000
60000
40000
20000
0
2.10
2.08
2.06
2.04
2.02
2.00
129377
0
965
730
0
N + 1
N - 2
N - 1
N
N + 2
-40
-15
10
35
60
85
DIGITAL OUTPUT NOISE
TEMPERATURE (°C)
8
_______________________________________________________________________________________
Dual 10-Bit, 80Msps, 3V, Low-Power ADC
with Internal Reference and Parallel Outputs
Pin Description
PIN
NAME
FUNCTION
1
COM
Common-Mode Voltage Input/Output. Bypass to GND with a ≥ 0.1µF capacitor.
Analog Supply Voltage. Bypass each supply pin to GND with a 0.1µF capacitor. The analog
supply voltage accepts a 2.7V to 3.6V input range.
2, 6, 11, 14, 15
V
DD
3, 7, 10, 13, 16
GND
INA+
INA-
INB-
INB+
CLK
Analog Ground
4
5
Channel ‘A’ Positive Analog Input. For single-ended operation, connect signal source to INA+.
Channel ‘A’ Negative Analog Input. For single-ended operation, connect INA- to COM.
Channel ‘B’ Negative Analog Input. For single-ended operation, connect INB- to COM.
Channel ‘B’ Positive Analog Input. For single-ended operation, connect signal source to INB+.
Converter Clock Input
8
9
12
T/B selects the ADC digital output format.
High: Two’s complement.
Low: Straight offset binary.
17
18
19
20
T/B
SLEEP
PD
Sleep Mode Input.
High: Deactivates the two ADCs, but leaves the reference bias circuit active.
Low: Normal operation.
Power-Down Input.
High: Power-down mode.
Low: Normal operation.
Output Enable Input.
High: Digital outputs disabled.
Low: Digital outputs enabled.
OE
21
22
D9B
D8B
D7B
D6B
D5B
D4B
D3B
D2B
D1B
D0B
OGND
Three-State Digital Output, Bit 9 (MSB), Channel B
Three-State Digital Output, Bit 8, Channel B
Three-State Digital Output, Bit 7, Channel B
Three-State Digital Output, Bit 6, Channel B
Three-State Digital Output, Bit 5, Channel B
Three-State Digital Output, Bit 4, Channel B
Three-State Digital Output, Bit 3, Channel B
Three-State Digital Output, Bit 2, Channel B
Three-State Digital Output, Bit 1, Channel B
Three-State Digital Output, Bit 0 (LSB), Channel B
Output Driver Ground
23
24
25
26
27
28
29
30
31, 34
Output Driver Supply Voltage. Bypass each supply pin to OGND with a 0.1µF capacitor. The
digital supply voltage accepts a 1.7V to 3.6V input range.
32, 33
OV
DD
35
36
37
38
39
D0A
D1A
D2A
D3A
D4A
Three-State Digital Output, Bit 0 (LSB), Channel A
Three-State Digital Output, Bit 1, Channel A
Three-State Digital Output, Bit 2, Channel A
Three-State Digital Output, Bit 3, Channel A
Three-State Digital Output, Bit 4, Channel A
_______________________________________________________________________________________
9
Dual 10-Bit, 80Msps, 3V, Low-Power ADC
with Internal Reference and Parallel Outputs
Pin Description (continued)
PIN
40
41
42
43
44
NAME
D5A
D6A
D7A
D8A
D9A
FUNCTION
Three-State Digital Output, Bit 5, Channel A
Three-State Digital Output, Bit 6, Channel A
Three-State Digital Output, Bit 7, Channel A
Three-State Digital Output, Bit 8, Channel A
Three-State Digital Output, Bit 9 (MSB), Channel A
Internal Reference Voltage Output. May be connected to REFIN through a resistor or a resistor
divider.
45
46
47
REFOUT
REFIN
REFP
Reference Input. V
= 2 x (V
- V
REFN
). Bypass to GND with a > 1nF capacitor.
REFIN
REFP
Positive Reference Input/Output. Conversion range is (V
with a > 0.1µF capacitor.
- V
REFN
). Bypass to GND
REFP
Negative Reference Input/Output. Conversion range is (V
with a > 0.1µF capacitor.
- V
). Bypass to GND
REFP
REFN
48
—
REFN
EP
Exposed Paddle. Connect to analog ground.
capacitors C2a and C2b. The amplifiers are used to
charge capacitors C1a and C1b to the same values
originally held on C2a and C2b. These values are then
presented to the first-stage quantizers and isolate the
pipelines from the fast-changing inputs. The wide input
bandwidth T/H amplifiers allow the MAX1181 to track
and sample/hold analog inputs of high frequencies
(> Nyquist). Both ADC inputs (INA+, INB+, INA-, and
INB-) can be driven either differentially or single-ended.
Match the impedance of INA+ and INA-, as well as
INB+ and INB-, and set the common-mode voltage to
Detailed Description
The MAX1181 uses a nine-stage, fully-differential
pipelined architecture (Figure 1), that allows for high-
speed conversion while minimizing power consump-
tion. Samples taken at the inputs move progressively
through the pipeline stages every half clock cycle.
Counting the delay through the output latch, the clock-
cycle latency is five clock cycles.
1.5-bit (two-comparator) flash ADCs convert the held-
input voltages into a digital code. The digital-to-analog
converters (DACs) convert the digitized results back
into analog voltages, which are then subtracted from
the original held-input signals. The resulting error sig-
nals are then multiplied by two, and the residues are
passed along to the next pipeline stages where the
process is repeated until the signals have been
processed by all nine stages. Digital error correction
compensates for ADC comparator offsets in each of
these pipeline stages and ensures no missing codes.
midsupply (V
/ 2) for optimum performance.
DD
Analog Inputs and Reference
Configurations
The full-scale range of the MAX1181 is determined by
the internally generated voltage difference between
REFP (V
REFIN
/ 2 + V
/ 4) and REFN (V
/ 2 -
DD
DD
REFIN
V
/ 4). The full-scale range for both on-chip ADCs is
adjustable through the REFIN pin, which is provided for
this purpose.
Input Track-and-Hold (T/H) Circuits
Figure 2 displays a simplified functional diagram of the
input track-and-hold (T/H) circuits in both track-and-
hold mode. In track mode, switches S1, S2a, S2b, S4a,
S4b, S5a and S5b are closed. The fully-differential cir-
cuits sample the input signals onto the two capacitors
(C2a and C2b) through switches S4a and S4b. S2a and
S2b set the common mode for the amplifier input, and
open simultaneously with S1, sampling the input wave-
form. Switches S4a and S4b are then opened before
switches S3a and S3b connect capacitors C1a and
C1b to the output of the amplifier and switch S4c is
closed. The resulting differential voltages are held on
REFOUT, REFP, COM (V
/ 2) and REFN are internally
DD
buffered low-impedance outputs.
The MAX1181 provides three modes of reference
operation:
• Internal reference mode
• Buffered external reference mode
• Unbuffered external reference mode
In the internal reference mode, connect the internal ref-
erence output REFOUT to REFIN through a resistor
(e.g., 10kΩ) or resistor divider, if an application
requires a reduced full-scale range.
10 ______________________________________________________________________________________
Dual 10-Bit, 80Msps, 3V, Low-Power ADC
with Internal Reference and Parallel Outputs
V
V
IN
V
V
OUT
IN
OUT
x2
x2
Σ
Σ
T/H
T/H
FLASH
ADC
FLASH
ADC
DAC
DAC
1.5 BITS
1.5 BITS
2-BIT FLASH
ADC
2-BIT FLASH
ADC
STAGE 1
STAGE 2
STAGE 8
STAGE 9
STAGE 1
STAGE 2
STAGE 8
STAGE 9
DIGITAL CORRECTION LOGIC
10
DIGITAL CORRECTION LOGIC
10
T/H
T/H
D9A–D0A
D9B–D0B
V
V
INB
INA
V
V
= INPUT VOLTAGE BETWEEN INA+ AND INA- (DIFFERENTIAL OR SINGLE-ENDED)
= INPUT VOLTAGE BETWEEN INB+ AND INB- (DIFFERENTIAL OR SINGLE-ENDED)
INA
INB
Figure 1. Pipelined Architecture––Stage Blocks
✕
✕
For stability and noise filtering purposes, bypass REFIN
with a > 10nF capacitor to GND. In internal reference
mode, REFOUT, COM, REFP, and REFN become low-
impedance outputs.
SNR = 20 log (1 / [2π x f
t
AJ
]),
10
IN
where f represents the analog input frequency and
IN
t
AJ
is the time of the aperture jitter.
Clock jitter is especially critical for undersampling
applications. The clock input should always be consid-
ered as an analog input and routed away from any ana-
log input or other digital signal lines.
In the buffered external reference mode, adjust the ref-
erence voltage levels externally by applying a stable
and accurate voltage at REFIN. In this mode, COM,
REFP, and REFN become outputs. REFOUT may be left
open or connected to REFIN through a > 10kΩ resistor.
In the unbuffered external reference mode, connect
REFIN to GND. This deactivates the on-chip reference
buffers for REFP, COM, and REFN. With their buffers
shut down, these nodes become high impedance and
may be driven through separate external reference
sources.
The MAX1181 clock input operates with a voltage thresh-
old set to V
/ 2. Clock inputs with a duty cycle other
DD
than 50% must meet the specifications for high and low
periods as stated in the Electrical Characteristics table.
System Timing Requirements
Figure 3 depicts the relationship between the clock
input, analog input, and data output. The MAX1181
samples at the rising edge of the input clock. Output
data for channels A and B is valid on the next rising
edge of the input clock. The output data has an internal
latency of five clock cycles. Figure 4 also determines
the relationship between the input clock parameters
and the valid output data on channels A and B.
Clock Input (CLK)
The MAX1181’s CLK input accepts CMOS-compatible
clock signals. Since the interstage conversion of the
device depends on the repeatability of the rising and
falling edges of the external clock, use a clock with low
jitter and fast rise and fall times (< 2ns). In particular,
sampling occurs on the rising edge of the clock signal,
requiring this edge to provide lowest possible jitter. Any
significant aperture jitter would limit the SNR perfor-
mance of the on-chip ADCs as follows:
Digital Output Data, Output Data Format
Selection (T/B), Output Enable (OE)
All digital outputs, D0A–D9A (Channel A) and D0B–D9B
(Channel B), are TTL/CMOS logic-compatible. There is a
______________________________________________________________________________________ 11
Dual 10-Bit, 80Msps, 3V, Low-Power ADC
with Internal Reference and Parallel Outputs
INTERNAL
BIAS
COM
S5a
S2a
C1a
S3a
S4a
S4b
INA+
INA-
OUT
OUT
C2a
C2b
S4c
S1
C1b
S3b
S5b
COM
S2b
INTERNAL
BIAS
CLK
INTERNAL
NONOVERLAPPING
CLOCK SIGNALS
HOLD
HOLD
INTERNAL
BIAS
TRACK
TRACK
COM
S5a
S2a
C1a
S3a
S4a
S4b
INB+
INB-
OUT
OUT
C2a
C2b
S4c
S1
MAX1181
C1b
S3b
S5b
COM
S2b
INTERNAL
BIAS
Figure 2. MAX1181 T/H Amplifiers
five clock cycle latency between any particular sample
and its corresponding output data. The output coding
can be chosen to be either straight offset binary or two’s
complement (Table 1) controlled by a single pin (T/B).
Pull T/B low to select offset binary and high to activate
two’s complement output coding. The capacitive load
on the digital outputs D0A–D9A and D0B–D9B should
be kept as low as possible (< 15pF), to avoid large digi-
tal currents that could feed back into the analog portion
of the MAX1181, thereby degrading its dynamic perfor-
mance. Using buffers on the digital outputs of the ADCs
can further isolate the digital outputs from heavy capaci-
tive loads. To further improve the dynamic performance
12 ______________________________________________________________________________________
Dual 10-Bit, 80Msps, 3V, Low-Power ADC
with Internal Reference and Parallel Outputs
5 CLOCK-CYCLE LATENCY
N
N + 1
N + 2
N + 3
N + 4
N + 5
N + 6
ANALOG INPUT
CLOCK INPUT
t
CLK
t
t
CH
D0
t
CL
DATA OUTPUT
D9A–D0A
N - 6
N - 6
N - 5
N - 5
N - 4
N - 4
N - 3
N - 3
N - 2
N - 1
N - 1
N
N
N + 1
DATA OUTPUT
D9B–D0B
N - 2
N + 1
Figure 3. System Timing Diagram
Table 1. MAX1181 Output Codes For Differential Inputs
STRAIGHT OFFSET
BINARY
DIFFERENTIAL INPUT
VOLTAGE*
TWO’S COMPLEMENT
T/B = 1
DIFFERENTIAL INPUT
T/B = 0
✕
V
511/512
+FULL SCALE - 1LSB
+ 1 LSB
11 1111 1111
10 0000 0001
10 0000 0000
01 1111 1111
00 0000 0001
00 0000 0000
01 1111 1111
00 0000 0001
00 0000 0000
11 1111 1111
10 0000 0001
10 0000 0000
REF
✕
V
1/512
REF
0
Bipolar Zero
✕
-V
1/512
- 1 LSB
REF
✕
-V
511/512
512/512
- FULL SCALE + 1 LSB
- FULL SCALE
REF
REF
✕
-V
*V
= V
- V
REFP REFN
REF
of the MAX1181 small-series resistors (e.g., 100Ω), add
to the digital output paths, close to the MAX1181.
value prior to the power-down. Pulling OE high, forces
the digital outputs into a high-impedance state.
Figure 4 displays the timing relationship between out-
put enable and data output valid, as well as power-
down/wake-up and data output valid.
Applications Information
Figure 5 depicts a typical application circuit containing
two single-ended to differential converters. The internal
Power-Down (PD) and Sleep
(SLEEP) Modes
The MAX1181 offers two power-save modes; sleep and
full power-down mode. In sleep mode (SLEEP = 1),
only the reference bias circuit is active (both ADCs are
disabled) and current consumption is reduced to
2.8mA.
reference provides a V
/ 2 output voltage for level-
DD
shifting purposes. The input is buffered and then split
to a voltage follower and inverter. One lowpass filter per
ADC suppresses some of the wideband noise associat-
ed with high-speed operational amplifiers. The user
may select the R
and C values to optimize the fil-
IN
ISO
ter performance to suit a particular application. For the
application in Figure 5, a R of 50Ω is placed before
ISO
To enter full power-down mode, pull PD high. With OE
simultaneously low, all outputs are latched at the last
the capacitive load to prevent ringing and oscillation.
_______________________________________________________________________________________ 13
Dual 10-Bit, 80Msps, 3V, Low-Power ADC
with Internal Reference and Parallel Outputs
The 22pF C capacitor acts as a small bypassing
IN
capacitor.
OE
Using Transformer Coupling
An RF transformer (Figure 6) provides an excellent
solution to convert a single-ended source signal to a
fully-differential signal, required by the MAX1181 for
optimum performance. Connecting the center tap of the
t
t
DISABLE
ENABLE
OUTPUT
D9A–D0A
HIGH IMPEDANCE
HIGH IMPEDANCE
VALID DATA
VALID DATA
transformer to COM provides a V
/ 2 DC level shift to
DD
OUTPUT
D9B–D0B
HIGH IMPEDANCE
HIGH IMPEDANCE
the input. Although a 1:1 transformer is shown, a step-
up transformer may be selected to reduce the drive
requirements. A reduced signal swing from the input
driver, such as an op amp, may also improve the over-
all distortion.
Figure 4. Output Timing Diagram
Grounding, Bypassing,
and Board Layout
In general, the MAX1181 provides better SFDR and
THD with fully-differential input signals, than a single-
ended drive, especially for high input frequencies. In
differential input mode, even-order harmonics are lower
as both inputs (INA+, INA- and/or INB+, INB-) are bal-
anced, and each of the ADC inputs only require half the
signal swing compared to single-ended mode.
The MAX1181 requires high-speed board layout design
techniques. Locate all bypass capacitors as close to
the device as possible, preferably on the same side as
the ADC, using surface-mount devices for minimum
inductance. Bypass V , REFP, REFN, and COM with
DD
two parallel 0.1µF ceramic capacitors and a 2.2µF
bipolar capacitor to GND. Follow the same rules to
Single-Ended AC-Coupled Input Signal
Figure 7 shows an AC-coupled, single-ended applica-
tion. Amplifiers, like the MAX4108, provide high-speed,
high bandwidth, low-noise, and low distortion to main-
tain the integrity of the input signal.
bypass the digital supply (OV ) to OGND. Multilayer
DD
boards with separate ground and power planes, pro-
duce the highest level of signal integrity. Consider the
use of a split ground plane arranged to match the phys-
ical location of the analog ground (GND) and the digital
output driver ground (OGND) on the ADCs package.
The two ground planes should be joined at a single
point, such that the noisy digital ground currents do not
interfere with the analog ground plane. The ideal loca-
tion of this connection can be determined experimental-
ly at a point along the gap between the two ground
planes, which produces optimum results. Make this
connection with a low-value, surface-mount resistor (1Ω
to 5Ω), a ferrite bead, or a direct short. Alternatively, all
ground pins could share the same ground plane, if the
ground plane is sufficiently isolated from any noisy, dig-
ital systems ground plane (e.g., downstream output
buffer or DSP ground plane). Route high-speed digital
signal traces away from the sensitive analog traces of
either channel. Make sure to isolate the analog input
lines to each respective converter to minimize channel-
to-channel crosstalk. Keep all signal lines short and
free of 90 degree turns.
Typical QAM Demodulation Application
The most frequently used modulation technique for digi-
tal communications application is the Quadrature
Amplitude Modulation (QAM). QAMs are typically found
in spread-spectrum based systems. A QAM signal rep-
resents a carrier frequency modulated in both amplitude
and phase. At the transmitter, modulating the baseband
signal with quadrature outputs, a local oscillator fol-
lowed by subsequent up-conversion can generate the
QAM signal. The result is an in-phase (I) and a quadra-
ture (Q) carrier component, where the Q component is
90 degrees phase-shifted with respect to the in-phase
component. At the receiver, the QAM signal is divided
down into its I and Q components, essentially represent-
ing the modulation process reversed. Figure 8 displays
the demodulation process performed in the analog
domain, using the dual-matched, 3V, 10-bit ADCs,
MAX1181 and the MAX2451 quadrature demodulators,
to recover and digitize the I and Q baseband signals.
Before being digitized by the MAX1181, the mixed-down
signal components may be filtered by matched analog
filters, such as Nyquist or pulse-shaping filters which
remove any unwanted images from the mixing process,
enhances the overall signal-to-noise (SNR) perfor-
mance, and minimizes intersymbol interference.
14 ______________________________________________________________________________________
Dual 10-Bit, 80Msps, 3V, Low-Power ADC
with Internal Reference and Parallel Outputs
+5V
0.1μF
LOWPASS FILTER
INA+
MAX4108
R
50Ω
ISO
0.1μF
300Ω
C
IN
22pF
0.1μF
-5V
600Ω
600Ω
300Ω
COM
0.1μF
+5V
+5V
0.1μF
0.1μF
600Ω
INPUT
0.1μF
0.1μF
LOWPASS FILTER
MAX4108
300Ω
300Ω
INA-
MAX4108
R
ISO
C
IN
22pF
50Ω
-5V
-5V
+5V
300Ω
300Ω
600Ω
MAX1181
0.1μF
LOWPASS FILTER
INB+
MAX4108
R
50Ω
ISO
0.1μF
300Ω
C
IN
22pF
0.1μF
-5V
600Ω
600Ω
300Ω
0.1μF
+5V
+5V
0.1μF
0.1μF
600Ω
INPUT
0.1μF
0.1μF
LOWPASS FILTER
MAX4108
300Ω
300Ω
INB-
MAX4108
R
ISO
50Ω
C
IN
22pF
-5V
-5V
300Ω
300Ω
600Ω
Figure 5. Typical Application for Single-Ended-to-Differential Conversion
______________________________________________________________________________________ 15
Dual 10-Bit, 80Msps, 3V, Low-Power ADC
with Internal Reference and Parallel Outputs
Dynamic Parameter Definitions
25Ω
INA+
Aperture Jitter
22pF
Figure 9 depicts the aperture jitter (t ), which is the
AJ
sample-to-sample variation in the aperture delay.
0.1μF
1
2
6
5
4
T1
V
IN
Aperture Delay
Aperture delay (t ) is the time defined between the
AD
COM
N.C.
falling edge of the sampling clock and the instant when
an actual sample is taken (Figure 9).
2.2μF
0.1μF
3
MINI-CIRCUITS
TT1–6
Signal-to-Noise Ratio (SNR)
For a waveform perfectly reconstructed from digital
samples, the theoretical maximum SNR is the ratio of
the full-scale analog input (RMS value) to the RMS
quantization error (residual error).
25Ω
INA-
INB+
22pF
22pF
MAX1181
25Ω
The ideal, theoretical minimum analog-to-digital noise is
caused by quantization error only and results directly
from the ADC’s resolution (N-Bits):
0.1μF
✕
SNR
= 6.02 N + 1.76
[max]
1
2
6
5
4
T1
V
IN
In reality, there are other noise sources besides quanti-
zation noise; thermal noise, reference noise, clock jitter,
etc. SNR is computed by taking the ratio of the RMS
signal to the RMS noise, which includes all spectral
components minus the fundamental, the first five har-
monics, and the DC offset.
N.C.
2.2μF
0.1μF
3
MINI-CIRCUITS
TT1–6
25Ω
INB-
Signal-to-Noise Plus Distortion (SINAD)
SINAD is computed by taking the ratio of the RMS sig-
nal to all spectral components minus the fundamental
and the DC offset.
22pF
Figure 6. Transformer-Coupled Input Drive
Effective Number of Bits (ENOB)
ENOB specifies the dynamic performance of an ADC at
a specific input frequency and sampling rate. An ideal
ADC’s error consists of quantization noise only. ENOB
is computed from:
Static Parameter Definitions
Integral Nonlinearity (INL)
Integral nonlinearity is the deviation of the values on an
actual transfer function from a straight line. This straight
line can be either a best straight-line fit or a line drawn
between the endpoints of the transfer function, once
offset and gain errors have been nullified. The static lin-
earity parameters for the MAX1181 are measured using
the best straight-line fit method.
SINAD−1.76
ENOB=
6.02
Total Harmonic Distortion (THD)
THD is typically the ratio of the RMS sum of the first four
harmonics of the input signal to the fundamental itself.
This is expressed as:
Differential Nonlinearity (DNL)
Differential nonlinearity is the difference between an
actual step-width and the ideal value of 1LSB. A DNL
error specification of less than 1LSB guarantees no
missing codes and a monotonic transfer function.
⎛
⎜
⎞
⎟
2
2
2
2
V2 + V3 + V4 + V5
THD = 20 × log
10
⎜
⎜
⎝
⎟
⎟
⎠
V
1
16 ______________________________________________________________________________________
Dual 10-Bit, 80Msps, 3V, Low-Power ADC
with Internal Reference and Parallel Outputs
REFP
1kΩ
1kΩ
R
50Ω
V
ISO
IN
0.1μF
INA+
COM
INA-
MAX4108
C
22pF
IN
100Ω
100Ω
REFN
0.1μF
R
50Ω
ISO
C
IN
22pF
REFP
MAX1181
1kΩ
R
50Ω
ISO
V
IN
0.1μF
INB+
MAX4108
C
IN
100Ω
100Ω
1kΩ
22pF
REFN
0.1μF
R
ISO
50Ω
INB-
C
IN
22pF
Figure 7. Using an Op Amp for Single-Ended, AC-Coupled Input Drive
MAX2451
INA+
INA-
0°
90°
DSP POST
PROCESSING
MAX1181
INB+
INB-
DOWNCONVERTER
÷
8
Figure 8. Typical QAM Application, Using the MAX1181
______________________________________________________________________________________ 17
Dual 10-Bit, 80Msps, 3V, Low-Power ADC
with Internal Reference and Parallel Outputs
where V is the fundamental amplitude, and V through
1
2
V
are the amplitudes of the 2nd- through 5th-order
harmonics.
5
CLK
Spurious-Free Dynamic Range (SFDR)
SFDR is the ratio expressed in decibels of the RMS
amplitude of the fundamental (maximum signal compo-
nent) to the RMS value of the next largest spurious
component, excluding DC offset.
ANALOG
INPUT
t
AD
t
AJ
SAMPLED
DATA (T/H)
Intermodulation Distortion (IMD)
The two-tone IMD is the ratio expressed in decibels of
either input tone to the worst 3rd-order (or higher) inter-
modulation products. The individual input tone levels
are at -6.5dB full scale.
HOLD
TRACK
TRACK
T/H
Figure 9. T/H Aperture Timing
Functional Diagram
V
DD
OGND
OV
DD
GND
INA+
10
10
OUTPUT
DRIVERS
PIPELINE
ADC
D9A–D0A
DEC
T/H
INA-
CLK
CONTROL
OE
INB+
INB-
10
10
PIPELINE
ADC
OUTPUT
DRIVERS
DEC
T/H
D9B–D0B
T/B
REFERENCE
PD
MAX1181
SLEEP
REFOUT
REFN COM REFP
REFIN
18 ______________________________________________________________________________________
Dual 10-Bit, 80Msps, 3V, Low-Power ADC
with Internal Reference and Parallel Outputs
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)
PACKAGE OUTLINE,
48L TQFP, 7x7x1.0mm EP OPTION
1
21-0065
G
2
______________________________________________________________________________________ 19
Dual 10-Bit, 80Msps, 3V, Low-Power ADC
with Internal Reference and Parallel Outputs
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)
PACKAGE OUTLINE,
48L TQFP, 7x7x1.0mm EP OPTION
2
21-0065
G
2
Revision History
Pages changed at Rev 1: 1–19
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
20 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2007 Maxim Integrated Products
is a registered trademark of Maxim Integrated Products, Inc.
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