The AD7656/AD7657/AD76581 contain six 16-/14-/12-bit， fast， low power， successive approximation ADCs all in the one package that is designed on the iCMOS? process （industrial CMOS）。 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， which dramatically reduces power consumption and package size. The AD7656/AD7657/AD7658 feature throughput rates up to 250 kSPS. The parts contain low noise， wide bandwidth， track-and-hold amplifiers that can handle input frequencies up to 12 MHz. The conversion process and data acquisition are controlled using CONVST signals and an internal oscillator. Three CONVST pins allow independent， simultaneous sampling of the three ADC pairs. The AD7656/AD7657/AD7658 all have a high speed parallel and serial interface， allowing the devices to interface with microprocessors or DSPs. In serial interface mode， the parts have a daisy-chain feature that allows multiple ADCs to connect to a single serial interface. The AD7656/ AD7657/AD7658 can accommodate true bipolar input signals in the ±4 × VREF range and ±2 × VREF range. The AD7656/ AD7657/AD7658 also contain an on-chip 2.5 V reference.