Dual Pseudo Differential 16-Bit, 1 MSPS

PulSAR ADC 12.0 mW in QSOP

Data Sheet

AD7902

Rev. 0

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FEATURES

16-bit resolution with no missing codes

Throughput: 1 MSPS

Low power dissipation

12.0 mW at 1 MSPS (total)

140 μW at 10 kSPS

INL: ±1.0 LSB typical, ±2.5 LSB maximum

SINAD: 91 dB at 1 kHz

THD: −105 dB at 1 kHz

Pseudo differential analog input range

Allows use of any input range

Easy to drive with the ADA4841-x

No pipeline delay

Single-supply 2.5 V operation with 1.8 V/2.5 V/3 V/5 V logic

interface

Serial port interface (SPI) QSPI/MICROWIRE/DSP compatible

20-lead QSOP package

Wide operating temperature range: −40°C to +125°C

APPLICATIONS

Battery-powered equipment

Communications

Automated test equipment (ATE)

Data acquisition

Medical instrumentation

Redundant measurement

Simultaneous sampling

GENERAL DESCRIPTION

The AD7902 is a dual 16-bit, successive approximation, analog-

to-digital converter (ADC) that operates from a single power

supply, VDDx, per ADC. It contains two low power, high speed,

16-bit sampling ADCs and a versatile serial port interface (SPI).

On the CNVx rising edge, the AD7902 samples an analog input,

IN−. The externally applied reference voltage of the REFx pins

VDDx. The power of the device scales linearly with throughput.

Using the SDIx inputs, the SPI-compatible serial interface can

also daisy-chain multiple ADCs on a single 3-wire bus and provide

an optional busy indicator. It is compatible with 1.8 V, 2.5 V, 3 V,

or 5 V logic, using the separate VIOx supplies.

The AD7902 is available in a 20-lead QSOP package with

operation specified from −40°C to +125°C.

Table 1. MSOP 14-/16-/18-Bit PulSAR® ADCs

Bits

100 kSPS

250 kSPS

400 kSPS

to 500 kSPS

1000 kSPS

ADC Driver

18

AD76911

AD76901

AD79821

ADA4941-1

ADA4841-x

16

AD7680

AD76851

AD76861

AD79801

ADA4941-1

AD7683

AD76871

AD76881

AD7903

ADA4841-x

AD7684

AD7694

AD76931

AD7902

14

AD7940

AD79421

AD79461

FUNCTIONAL BLOCK DIAGRAM

Figure 1.

GND

VDD1 VDD2

2.5V

REF1 REF2

REF = 2.5V TO 5V

ADC1

IN1+

IN1–

VIO1

SDI1

SCK1

CNV1

SDO1

VIO1/VIO2

SDI1/SDI2

SCK1/SCK2

CNV1/CNV2

SDO1

ADC2

IN2+

IN2–

VIO2

SDI2

SCK2

CNV2

SDO2

SDO2

3-WIRE OR 4-WIRE

INTERFACE

(SPI, CS, AND

CHAIN MODES)

AD7902

0V TO VREF

0V TO VREF