GENERAL DESCRIPTION

The AD7942 is a 14-bit, charge redistribution, successive approximation PulSAR® ADC that operates from a single power supply, 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 analog input, IN+, between 0 V to VREF with respect to a ground sense, IN−. The reference voltage, VREF, is applied externally and is set up to be the supply voltage. Its power scales linearly with the throughput.

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 @ 20 kHz

THD: −100 dB @ 20 kHz

Pseudo differential analog input range

0 V to VREF with VREF up to VDD

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

Serial interface SPI-/QSPI-/MICROWIRE-/

DSP-compatible

Daisy-chaining for multiple ADCs and busy indicator

Power dissipation

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

1.25 μW @ 2.5 V/100 SPS

Standby current: 1 nA

10-lead package: MSOP and 3 mm × 3 mm QFN (LFCSP)

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

APPLICATIONS

Battery-powered equipment

Data acquisition

Instrumentation

Medical instruments

Process controls