14-Bit, 2.5 MSPS, PulSAR 15.5 mW ADC in LFCSP

The AD7944 is a 14-bit, 2.5 MSPS successive approximation analog-to-digital converter (SAR ADC). It contains a low power, high speed, 14-bit sampling ADC, an internal conversion clock, an internal reference (and buffer), error correction circuits, and a versatile serial interface port. On the rising edge of CNV, the AD7944 samples an analog input, IN+, between 0 V and VREF with respect to a ground sense, IN−. The AD7944 features a very high sampling rate turbo mode (TURBO high) and a reduced power normal mode (TURBO low) for low power applications where the power is scaled with the throughput.

In normal mode (TURBO low), 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 provide an optional busy indicator. The serial interface is compatible with 1.8 V, 2.5 V, and 2.7 V supplies using the separate VIO supply.

The AD7944 is available in a 20-lead LFCSP with operation specified from −40°C to +85°C.

APPLICATIONS

* Battery-powered equipment

* Communications

* ATE

* Data acquisition systems

* Medical instruments

* 14-bit resolution with no missing codes

* Throughput: 2.5 MSPS (TURBO high), 2.0 MSPS (TURBO low)

* Low power dissipation

15.5 mW at 2.5 MSPS, with external reference

28 mW at 2.5 MSPS, with internal reference

* SNR

84 dB, with on-chip reference

84.5 dB, with external reference

* 4.096 V internal reference: typical drift of

±10 ppm/°C