ANALOG DEVICES AD7709 handbook
Datasheet
AD7709 is a 16-bit differential input analog-to-digital converter with a programmable gain front end and switchable current sources that supports absolute and ratiometric measurements. It supports single 3 V and 5 V operation and has a 16-bit no missing codes peak-to-peak resolution at 20 Hz. AD7709 uses a 3-wire serial SPI, QSPI, MICROWIRE and DSP compatible Schmitt trigger SCLK interface.