The AD79851 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