14-Bit, 250 kSPS PulSAR,

Pseudo Differential ADC in MSOP/LFCSP

Data Sheet

AD7942

Rev. C

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FEATURES

14-bit resolution with no missing codes

Throughput: 250 kSPS

INL: ±0.4 LSB typical, ±1 LSB maximum (±0.0061% of FSR)

SINAD: 85 dB at 20 kHz

THD: −100 dB at 20 kHz

Pseudo differential analog input range

No pipeline delay

Single-supply 2.3 V to 5.5 V operation with

1.8 V/2.5 V/3 V/5 V logic interface

Proprietary serial interface

SPI-/QSPI-/MICROWIRE-/DSP-compatible1

Daisy-chaining for multiple ADCs and busy indicator

Power dissipation

1.25 mW at 2.5 V/100 kSPS, 3.6 mW at 5 V/100 kSPS

1.25 μW at 2.5 V/100 SPS

Standby current: 1 nA

10-lead package: MSOP and 3 mm × 3 mm LFCSP

Pin-for-pin compatible with the 16-bit AD7685

APPLICATIONS

Battery-powered equipment

Data acquisition

Instrumentation

Medical instruments

Process controls

APPLICATION DIAGRAM

AD7942

REF

GND

VDD

IN+

IN–

VIO

SDI

SCK

SDO

CNV

1.8V TO VDD

3- OR 4-WIRE INTERFACE

(SPI, DAISY CHAIN, CS)

0.5V TO 5V

2.5V TO 5V

Figure 1.

GENERAL DESCRIPTION

The AD7942 is a 14-bit, charge redistribution, successive approxi-

mation PulSAR

VDD, between 2.3 V to 5.5 V. It contains a low power, high

speed, 14-bit sampling ADC with no missing codes, an internal

conversion clock, and a versatile serial interface port. The part

also contains a low noise, wide bandwidth, short aperture delay

track-and-hold circuit. On the CNV rising edge, it samples an

is set up to be the supply voltage. Its power scales linearly with

the throughput.

The SPI-compatible serial interface also features the ability,

using the SDI input, to daisy-chain several ADCs on a single

3-wire bus and provides an optional busy indicator. It is com-

patible with 1.8 V, 2.5 V, 3 V, or 5 V logic using a separate

supply (VIO).

The AD7942 is housed in a 10-lead MSOP or a 10-lead LFCSP

package yet fits in the same size footprint as the 8-lead MSOP

or SOT-23. Operation for the AD7942 is specified from −40°C

to +85°C.

Table 1. MSOP, LFCSP/SOT-23, 14-/16-/18-Bit ADCs

Type

100 kSPS

250 kSPS

400 kSPS to 500 kSPS

≥1000 kSPS

ADC Driver

14-Bit

AD7940

AD79421

AD79461

16-Bit

AD7680

AD76851

AD76861

AD79801

ADA4941-x

AD7683

AD76871

AD76881

AD79831

ADA4841-x

AD7684

AD7694

AD76931

18-Bit

AD76911

AD76901

AD79821

ADA4941-x

AD79841

ADA4841-x