The AD73281 is an 8-channel， 12-bit plus sign successive approximation ADC designed on the iCMOS? （industrial CMOS） process. iCMOS is a process combining high voltage silicon with submicron CMOS and complementary bipolar technologies. It enables the development of a wide range of high performance analog ICs capable of 33 V operation in a footprint that no previous generation of high voltage parts could achieve. Unlike analog ICs using conventional CMOS processes， iCMOS components can accept bipolar input signals while providing increased performance， dramatically reduced power consumption， and reduced package size. The AD7328 can accept true bipolar analog input signals. The AD7328 has four software-selectable input ranges： ±10 V， ±5 V， ±2.5 V， and 0 V to +10 V. Each analog input channel can be independently programmed to one of the four input ranges. The analog input channels on the AD7328 can be programmed to be single-ended， true differential， or pseudo differential. The ADC contains a 2.5 V internal reference. The AD7328 also allows for external reference operation. If a 3 V reference is applied to the REFIN/OUT pin， the AD7328 can accept a true bipolar ±12 V analog input. Minimum ±12 V VDD and VSS supplies are required for the ±12 V input range. The ADC has a high speed serial interface that can operate at throughput rates up to 1 MSPS.