AD7942 Analog Devices Data Sheet Manual

14-Bit, 250 k SPS Pul SAR,

Pseudo Differential ADC in MSOP/QFN

AD7942 FEATURES APPLICATION DIAGRAM

0.5V TO 5V 2.5V TO 5V

14-bit resolution with no missing codes Throughput: 250 k SPS INL: ±0.4 LSB typical, ±1 LSB maximum (±0.0061% of FSR)

SINAD: 85 d B @ 20 k Hz REF VDD VIO 1.8V TO VDD

0V TO VREF

THD: −100 d B @ 20 k Hz IN+

AD7942 SCK 3- OR 4-WIRE INTERFACE

Pseudo differential analog input range IN–

SDO (SPI, DAISY CHAIN, CS)

0 V to VREF with VREF up to VDD GND CNV 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

Figure 1.

Serial interface SPI-/QSPI-/MICROWIRE-/ DSP-compatible GENERAL DESCRIPTION Daisy-chaining for multiple ADCs and busy indicator

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

Power dissipation

mation Pul SAR® ADC that operates from a single power supply,

1.25 m W @ 2.5 V/100 k SPS, 3.6 m W @ 5 V/100 k SPS

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

1.25 μW @ 2.5 V/100 SPS

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

Standby current: 1 n A

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

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

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

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

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

APPLICATIONS analog input, IN+, between 0 V to VREF with respect to a ground

sense, IN−. The reference voltage, VREF, is applied externally and

Battery-powered equipment ww.BDTIC.c m/ADI

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

Data acquisition

the throughput.

Instrumentation Medical instruments The SPI-compatible serial interface also features the ability, Process controls 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 QFN (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, QFN (LFCSP)/SOT-23, 14-/16-/18-Bit ADCs

Type 100 k SPS 250 k SPS 400 k SPS to 500 k SPS ≥1000 k SPS ADC Driver 14-Bit AD7940 AD79421 AD79461 16-Bit AD7680 AD76861 AD79801 AD76851 ADA4941-x AD7683 AD76871 AD76881 AD79831 ADA4841-x AD7684 AD7694 AD76931 18-Bit AD76911 AD76901 AD79821 ADA4941-x AD79841 ADA4841-x

1 Pin-for-pin compatible to the AD7942.

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