MAXIM MAX1185 Technical data

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.

General Description

The MAX1185 is a 3V, dual 10-bit analog-to-digital con­verter (ADC) featuring fully-differential wideband track­and-hold (T/H) inputs, driving two pipelined, nine-stage
ADCs. The MAX1185 is optimized for low-power, high
dynamic performance applications in imaging, instru­mentation, and digital communication applications. This
ADC operates from a single 2.7V to 3.6V supply, con­suming only 105mW while delivering a typical signal-to­noise ratio (SNR) of 59.5dB at an input frequency of

7.5MHz and a sampling rate of 20Msps. Digital outputs
A and B are updated alternating on the rising (CHA)
and falling (CHB) edge of the clock. The T/H driven
input stages incorporate 400MHz (-3dB) input ampli­fiers. The converters may also be operated with single­ended inputs. In addition to low operating power, the
MAX1185 features a 2.8mA sleep mode as well as a
1µA power-down mode to conserve power during idle
periods.

An internal 2.048V precision bandgap reference sets
the full-scale range of the ADC. A flexible reference
structure allows the use of this internal or an externally
derived reference, if desired for applications requiring
increased accuracy or a different input voltage range.

The MAX1185 features parallel, multiplexed, CMOS­compatible three-state outputs. The digital output for­mat can be 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 interfacing. The MAX1185 is available in a 7mm
x 7mm, 48-pin TQFP package, and is specified for the
extended industrial (-40°C to +85°C) temperature
range.

Pin-compatible, nonmultiplexed. high-speed versions of
the MAX1185 are also available. Refer to the MAX1180
data sheet for 105Msps, the MAX1181 data sheet for
80Msps, the MAX1182 data sheet for 65Msps, the
MAX1183 data sheet for 40Msps, and the MAX1184
data sheet for 20Msps.

Applications

High Resolution Imaging

I/Q Channel Digitization

Multichannel IF Sampling

Instrumentation

Video Application

Ultrasound

Features

o Single 3V Operation
o Excellent Dynamic Performance:

59.5dB SNR at f

IN

= 7.5MHz

74dB SFDR at f

IN

= 7.5MHz

o Low Power:

35mA (Normal Operation)

2.8mA (Sleep Mode)
1µA (Shutdown Mode)

o 0.02dB Gain and 0.25° Phase Matching
o Wide ±1Vp-p Differential Analog Input Voltage

Range

o 400MHz, -3dB Input Bandwidth
o On-Chip 2.048V Precision Bandgap Reference
o Single 10-Bit Bus for Multiplexed, Digital Outputs
o User-Selectable Output Format—Two’s

Complement or Offset Binary

o 48-Pin TQFP Package with Exposed Pad for

Improved Thermal Dissipation

MAX1185

Dual 10-Bit, 20Msps, 3V, Low-Power ADC with

Internal Reference and Multiplexed Parallel Outputs

________________________________________________________________

Maxim Integrated Products

1

Pin Configuration

19-2175; Rev 3; 5/11

Ordering Information

*

EP = Exposed pad.

+

Denotes a lead(Pb)-free/RoHS-compliant package.

/V denotes an automotive qualified part.

Pin-Compatible Versions table at end of data sheet.

PART

TEMP

RANGE

MAX1185ECM -40°C to +85°C 48 TQFP-EP*

MAX1185ECM+ -40°C to +85°C 48 TQFP-EP*

MAX1185ECM/V+ -40°C to +85°C 48 TQFP-EP*

PIN-PACKAGE

REFN

REFP

REFIN

REFOUT

D9A/B

D8A/B

D7A/B

D6A/B

D5A/B

D4A/B

D3A/B

D2A/B

4847464544434241403938

COM

1

V

2

DD

GND

3

INA+

4

INA-

5

V

6

DD

GND

7

INB-

8

INB+

9

GND

10

V

11

DD

CLK

12

1314151617181920212223

GND

NOTE: THE PIN 1 INDICATOR FOR LEAD-FREE
PACKAGES IS REPLACED BY A "+" SIGN.

EP

DDVDD

V

MAX1185

PD

T/B

GND

SLEEP

48 TQFP-EP

OE

N.C.

N.C.

N.C.

37

24

N.C.

36

D1A/B
D0A/B

35

OGND

34

OV

33

DD

OV

32

DD

OGND

31

A/B

30

N.C.

29

N.C.

28

N.C.

27

N.C.

26

N.C.

25

MAX1185

Dual 10-Bit, 20Msps, 3V, Low-Power ADC with
Internal Reference and Multiplexed Parallel Outputs

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VDD= 3V, OVDD= 2.5V, 0.1µF and 1µF capacitors from REFP, REFN, and COM to GND; REFOUT connected to REFIN through a
10kΩ resistor, V

IN

= 2Vp-p (differential w.r.t. COM), CL= 10pF at digital outputs (Note 1), f

CLK

= 20MHz, TA= T

MIN

to T

MAX

, unless

otherwise noted. Typical values are at T

A

= +25°C.) (Note 2)

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.

VDD, OVDDto GND ...............................................-0.3V to +3.6V

OGND to GND.......................................................-0.3V to +0.3V

INA+, INA-, INB+, INB- to GND ...............................-0.3V to V

DD

REFIN, REFOUT, REFP, REFN, COM,

CLK to GND............................................-0.3V to (V

DD

+ 0.3V)

OE, PD, SLEEP, T/B, D9A/B–D0A/B,

A/B to OGND .......................................-0.3V to (OV

DD

+ 0.3V)

Continuous Power Dissipation (T

A

= +70°C)
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

Soldering Temperature (reflow)

Lead(Pb)-free..............................................................+260°C

Containing lead(Pb) ....................................................+240°C

DC ACCURACY

Resolution 10 Bits

Integral Nonlinearity INL fIN = 7.5MHz ±0.5 ±1.5 LSB

Differential Nonlinearity DNL fIN = 7.5MHz, no missing codes guaranteed ±0.25 ±1.0 LSB

Offset Error < ±1 ±1.9 % FS

Gain Error 0 ±2% FS

ANALOG INPUT

Differential Input Voltage
Range

Common-Mode Input Voltage
Range

Input Resistance R

Input Capacitance C

CONVERSION RATE

Maximum Clock Frequency f

Data Latency

DYNAMIC CHARACTERISTICS

Signal-to-Noise Ratio
(Note 3)

Signal-to-Noise and Distortion
(Note 3)

Spurious-Free Dynamic Range
(Note 3)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

V

DIFF

V

CLK

SNR

SINAD

SFDR

Differential or single-ended inputs ±1.0 V

CM

Switched capacitor load 100 kΩ

IN

IN

CHA 5

CHB 5.5

f

INA or B

f

INA or B

f

INA or B

f

INA or B

f

INA or B

f

INA or B

= 7.5MHz, TA = +25°C 57.3 59.5

= 12MHz 59.4

= 7.5MHz, TA = +25°C 57 59.4

= 12MHz 59.2

= 7.5MHz, TA = +25°C 64 74

= 12MHz 72

20 MHz

VDD/2

± 0.5

5pF

V

Clock

cycles

dB

dB

dBc

MAX1185

Dual 10-Bit, 20Msps, 3V, Low-Power ADC with

Internal Reference and Multiplexed Parallel Outputs

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VDD= 3V, OVDD= 2.5V, 0.1µF and 1µF capacitors from REFP, REFN, and COM to GND; REFOUT connected to REFIN through a
10kΩ resistor, V

IN

= 2Vp-p (differential w.r.t. COM), CL= 10pF at digital outputs (Note 1), f

CLK

= 20MHz, TA= T

MIN

to T

MAX

, unless

otherwise noted. Typical values are at T

A

= +25°C.) (Note 2)

Total Harmonic Distortion
(First 4 Harmonics) (Note 3)

Third-Harmonic Distortion
(Note 3)

Intermodulation Distortion IMD

Small-Signal Bandwidth Input at -20dBFS, differential inputs 500 MHz

Full-Power Bandwidth FPBW Input at -0.5dBFS, differential inputs 400 MHz

Aperture Delay t

Aperture Jitter t

Overdrive Recovery Time For 1.5x full-scale input 2 ns

Differential Gain ±1%

Differential Phase ±0.25 D egr ees

Output Noise INA+ = INA- = INB+ = INB- = COM 0.2 LSB

INTERNAL REFERENCE

Reference Output Voltage REFOUT

Reference Temperature
Coefficient

Load Regulation 1.25 mV/mA

BUFFERED EXTERNAL REFERENCE (V

REFIN Input Voltage V

Positive Reference Output
Voltage

Negative Reference Output
Voltage

Differential Reference Output
Voltage Range

REFIN Resistance R

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

f

REF

REFIN

INA or B

f

INA or B

f

INA or B

f

INA or B

f

INA or B

f

I N A o r B

= 2.048V)

REF

THD

HD3

AD

AJ

TC

REFIN

V

REFP

V

REFN

ΔVREF ΔV

REFIN

= 7.5MHz, TA = +25°C -72 -64

= 12MHz -71

= 7.5MHz -74

= 12MHz -72

= 11.9852MHz at -6.5dBFS,
= 12.8934M H z at - 6.5d BFS ( N ote 4)

= V

REFP

- V

REFN

-76 dBc

1ns

2ps

2.048
±3%

60 ppm/°C

2.048 V

2.012 V

0.988 V

0.95 1.024 1.10 V

> 50 MΩ

dBc

dBc

RMS

RMS

V

MAX1185

Dual 10-Bit, 20Msps, 3V, Low-Power ADC with
Internal Reference and Multiplexed Parallel Outputs

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(VDD= 3V, OVDD= 2.5V, 0.1µF and 1µF capacitors from REFP, REFN, and COM to GND; REFOUT connected to REFIN through a
10kΩ resistor, V

IN

= 2Vp-p (differential w.r.t. COM), CL= 10pF at digital outputs (Note 1), f

CLK

= 20MHz, TA= T

MIN

to T

MAX

, unless

otherwise noted. Typical values are at T

A

= +25°C.) (Note 2)

Maximum REFP, COM Source
Current

Maximum REFP, COM Sink
Current

Maximum REFN Source Current I

Maximum REFN Sink Current I

UNBUFFERED EXTERNAL REFERENCE (V

REFP, REFN Input Resistance

Differential Reference Input
Voltage

COM Input Voltage V

REFP Input Voltage V

REFN Input Voltage V

DIGITAL INPUTS (CLK, PD, OE, SLEEP, T/B)

Input High Threshold V

Input Low Threshold V

Input Hysteresis V

Input Leakage

Input Capacitance C

DIGITAL OUTPUTS (D0A/B–D9A/B, A/B)

Output-Voltage Low V

Output-Voltage High V

Three-State Leakage Current I

Three-State Output Capacitance C

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

I

SOURCE

I

SINK

SOURCE

SINK

R

REFP

R

REFN

ΔV

REF

COM

REFP

REFN

IH

IL

HYST

I

IH

I

IL

IN

OLISINK

OH

LEAK

OUT

= AGND, reference voltage applied to REFP, REFN, and COM)

REFIN

,

Measured between REFP and COM, and
REFN and COM

ΔV

= V

REF

CLK

PD, OE, SLEEP, T/B

REFP

- V

REFN

0.8

x V

0.8

x OV

DD

CLK

PD, OE, SLEEP, T/B

VIH = OV

DD

or V

(CLK) ±5

DD

VIL = 0 ±5

= -200µA 0.2 V

OV

I

SOURCE

OE = OV
OE = OV

= 200µA

DD

DD

DD

- 0.2

5mA

-250 µA

250 µA

-5 mA

4kΩ

1.024

±10%

VDD/2
±10%

V

+

COM

ΔV

/2

REF

V

-

COM

/2

ΔV

REF

DD

0.2

x V

DD

0.2

x OV

DD

0.1 V

5pF

±10 µA

5pF

V

V

V

V

V

V

µA

V

MAX1185

Dual 10-Bit, 20Msps, 3V, Low-Power ADC with

Internal Reference and Multiplexed Parallel Outputs

_______________________________________________________________________________________ 5

ELECTRICAL CHARACTERISTICS (continued)

(VDD= 3V, OVDD= 2.5V, 0.1µF and 1µF capacitors from REFP, REFN, and COM to GND; REFOUT connected to REFIN through a
10kΩ resistor, V

IN

= 2Vp-p (differential w.r.t. COM), CL= 10pF at digital outputs (Note 1), f

CLK

= 20MHz, TA= T

MIN

to T

MAX

, unless

otherwise noted. Typical values are at T

A

= +25°C.) (Note 2)

Note 1: Equivalent dynamic performance is obtainable over full OVDDrange with reduced CL.
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

IH

, VIL. Parameter guaranteed by design.

Note 6: With REFIN driven externally, REFP, COM, and REFN are left unconnected while powered down.

POWER REQUIREMENTS

Analog Supply Voltage Range V

Output Supply Voltage Range OV

Analog Supply Current I

Output Supply Current I

Power Dissipation PDISS

Power-Supply Rejection Ratio PSRR

TIMING CHARACTERISTICS

CLK Rise to CHA Output Data
Valid

CLK Fall to CHB Output Data
Valid

Clock Rise/Fall to A/B Rise/Fall
Time

Output Enable Time t

Output Disable Time t

CLK Pulse Width High t

CLK Pulse Width Low t

Wake-Up Time t

CHANNEL-TO-CHANNEL MATCHING

Crosstalk f

Gain Matching f

Phase Matching f

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

DD

DD

Operating, f

VDD

OVDD

t

DOA

t

DOB

t

DA/B

ENABLE

DISABLE

CH

WAKE

Sleep mode 2.8
Shutdown, clock idle, PD = OE = OV

Operating, CL = 15pF,
f

INA or B

Sleep mode 100
Shutdown, clock idle, PD = OE = OV

Operating, f

Sleep mode 8.4
Shutdown, clock idle, PD = OE = OV

Offset ±0.2 mV/V

Gain ±0.1 %/V

Figure 3 (Note 5) 5 8 ns

Figure 3 (Note 5) 5 8 ns

Figure 4 10 ns

Figure 4 1.5 ns

Figure 3, clock period: 50ns

Figure 3, clock period: 50ns

CL

Wake-up from sleep mode (Note 6) 0.51

Wake-up from shutdown (Note 6) 1.5

INA or B

INA or B

INA or B

= 7.5MHz at -0.5dBFS 35 50

INA or B

DD

= 7.5MHz at -0.5dBFS

DD

= 7.5MHz at -0.5dBFS 105 150

INA or B

DD

= 7.5MHz at -0.5dBFS -70 dB

= 7.5MHz at -0.5dBFS 0.02 ±0.2 dB

= 7.5MHz at -0.5dBFS 0.25 D eg r ees

2.7 3.0 3.6 V

1.7 2.5 3.6 V

115µA

9mA

210

345µW

6ns

25 ± 7.5

25 ± 7.5

mA

µA

mW

ns

ns

µs

MAX1185

Dual 10-Bit, 20Msps, 3V, Low-Power ADC with
Internal Reference and Multiplexed Parallel Outputs

6 _______________________________________________________________________________________

Typical Operating Characteristics

(VDD= 3V, OVDD= 2.5V, V

REFIN

= 2.048V, differential input at -0.5dBFS, f

CLK

= 20MHz, CL≈ 10pF, TA= +25°C, unless otherwise noted.)

-100

-80

-90

-60

-70

-40

-50

-30

-10

-20

0

023415679810

FFT PLOT CHA (DIFFERENTIAL INPUT,

8192-POINT DATA RECORD)

MAX1185 toc01

ANALOG INPUT FREQUENCY (MHz)

AMPLITUDE (dB)

CHA

f

CLK

= 20.0005678MHz

f

INA

= 5.9742906MHz

f

INB

= 7.5343935MHz

A

INA

= -0.525dBFS

HD3

HD2

-100

-80

-90

-60

-70

-40

-50

-30

-10

-20

0

0 23415679810

FFT PLOT CHB (DIFFERENTIAL INPUT,

8192-POINT DATA RECORD)

MAX1185 toc02

ANALOG INPUT FREQUENCY (MHz)

AMPLITUDE (dB)

CHB

f

CLK

= 20.0005678MHz

f

INA

= 5.9742906MHz

f

INB

= 7.5243935MHz

A

INA

= -0.462dBFS

HD3

HD2

-100

-80

-90

-60

-70

-40

-50

-30

-10

-20

0

0 2341 567 9810

FFT PLOT CHA (DIFFERENTIAL INPUT,

8192-POINT DATA RECORD)

MAX1185 toc03

ANALOG INPUT FREQUENCY (MHz)

AMPLITUDE (dB)

CHA

f

CLK

= 20.0005678MHz

f

INA

= 7.5343935MHz

f

INB

= 11.9852035MHz

A

INA

= -0.489dBFS

HD3

HD2

-100

-80

-90

-60

-70

-40

-50

-30

-10

-20

0

02341 567 9810

FFT PLOT CHB (DIFFERENTIAL INPUT,

8192-POINT DATA RECORD)

MAX1185 toc04

ANALOG INPUT FREQUENCY (MHz)

AMPLITUDE (dB)

CHB

f

CLK

= 20.0005678MHz

f

INA

= 7.5343935MHz

f

INB

= 11.9852035MHz

A

INA

= -0.471dBFS

HD3

HD2

-100

-80

-90

-60

-70

-40

-50

-30

-10

-20

0

0 2341 567 9810

TWO-TONE IMD PLOT (DIFFERENTIAL INPUT,

8192-POINT DATA RECORD)

MAX1185 toc05

ANALOG INPUT FREQUENCY (MHz)

AMPLITUDE (dB)

IM2

IM3

IM3

f

CLK

= 20.0005678MHz

f

IN1

= 11.9852035MHz

f

IN2

= 12.8934324MHz

A

IN

= -6.5dBFS

f

IN2

f

IN1

57

56

55

59

58

60

61

0 5 10 15 20 25 30 35 40 45

SIGNAL-TO-NOISE RATIO

vs. ANALOG INPUT FREQUENCY

MAX1185 toc06

ANALOG INPUT FREQUENCY (MHz)

SNR (dB)

CHA

CHB

62

60

58

54

56

0 5 10 15 20 25 30 35 40 45

SIGNAL-TO-NOISE AND DISTORTION

vs. ANALOG INPUT FREQUENCY

MAX1185 toc07

ANALOG INPUT FREQUENCY (MHz)

SINAD (dB)

CHB

CHA

-72

-76

-80

-68

-64

-60

TOTAL HARMONIC DISTORTION
vs. ANALOG INPUT FREQUENCY

MAX1185 toc08

ANALOG INPUT FREQUENCY (MHz)

THD (dBc)

0 5 10 15 20 25 30 35 40 45

CHA

CHB

60

64

72

68

76

80

SPURIOUS-FREE DYNAMIC RANGE

vs. ANALOG INPUT FREQUENCY

MAX1185 toc09

ANALOG INPUT FREQUENCY (MHz)

SFDR (dBc)

0 5 10 15 20 25 30 35 40 45

CHA

CHB

MAX1185

Dual 10-Bit, 20Msps, 3V, Low-Power ADC with

Internal Reference and Multiplexed Parallel Outputs

_______________________________________________________________________________________

7

Typical Operating Characteristics (continued)

(VDD= 3V, OVDD= 2.5V, V

REFIN

= 2.048V, differential input at -0.5dBFS, f

CLK

= 20MHz, CL≈ 10pF, TA= +25°C, unless otherwise noted

-8

-4

-6

0

-2

4

2

6

1 10 100 1000

FULL-POWER INPUT BANDWIDTH

vs. ANALOG INPUT FREQUENCY, SINGLE-ENDED

MAX1185 toc10

ANALOG INPUT FREQUENCY (MHz)

GAIN (dB)

-8

-4

-6

0

-2

4

2

6

1 10 100 1000

SMALL-SIGNAL INPUT BANDWIDTH

vs. ANALOG INPUT FREQUENCY, SINGLE-ENDED

MAX1185 toc11

ANALOG INPUT FREQUENCY (MHz)

GAIN (dB)

VIN = 100mV

P-P

35

45

40

55

50

60

65

-20 0

SIGNAL-TO-NOISE RATIO

vs. ANALOG INPUT POWER (f

IN

= 7.53MHz)

MAX1185 toc12

ANALOG INPUT POWER (dBFS)

SNR (dB)

-12-16 -8 -4

35

45

40

55

50

60

65

-20 0

SIGNAL-TO-NOISE PLUS DISTORTION

vs. ANALOG INPUT POWER (f

IN

= 7.53MHz)

MAX1185 toc13

ANALOG INPUT POWER (dBFS)

SINAD (dB)

-12-16 -8 -4

-85

-80

-75

-65

-70

-60

-55

-20 -12-16 -8 -4 0

TOTAL HARMONIC DISTORTION

vs. ANALOG INPUT POWER (f

IN

= 7.53MHz)

MAX1185 toc14

ANALOG INPUT POWER (dBFS)

THD (dBc)

60

55

75

70

65

85

80

90

-20 -12-16 -8 -4 0

SPURIOUS-FREE DYNAMIC RANGE

vs. ANALOG INPUT POWER (f

IN

= 7.53MHz)

MAX1185 toc15

ANALOG INPUT POWER (dBFS)

SFDR (dBc)

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0 256128 384 512 640 768 896 1024

INTEGRAL NONLINEARITY

(BEST END-POINT FIT)

MAX1185 toc16

DIGITAL OUTPUT CODE

INL (LSB)

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0 256128 384 512 640 768 896 1024

DIFFERENTIAL NONLINEARITY

MAX1185 toc17

DIGITAL OUTPUT CODE

DNL (LSB)

-0.1

-0.2

0.1

0

0.3

0.2

0.4

-40 85

GAIN ERROR vs. TEMPERATURE

MAX1185 toc18

TEMPERATURE (°C)

GAIN ERROR (%FS)

10-15 35 60

CHB

CHA