16-Bit, 2.5 MSPS PulSAR 11 mW ADC in QFN

The AD7985 is a 16-bit, 2.5 MSPS successive approximation analog-to-digital converter (SAR ADC). It contains a low power, high speed, 16-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 AD7985 samples an analog input, IN+, between 0 V and REF with respect to a ground sense, IN−. The AD7985 features a very high sampling rate turbo mode (TURBO is high) and a reduced power normal mode (TURBO is low) for low power applications where the power is scaled with the throughput.

In normal mode (TURBO is 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. It is compatible with 1.8 V, 2.5 V, and 2.7 V supplies using the separate VIO supply.

The AD7985 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

* 16-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

* INL: ±0.7 LSB typical, ±1.5 LSB maximum

* SNR

* 88.5 dB, with on-chip reference

* 90 dB, with external reference

* 4.096 V internal reference: typical drift of ±10 ppm/°C

* Pseudo differential analog input voltage range

* 0 V to VREF with VREF up to 5.0 V

* Allows use of any input range

* See data sheet for additional features