The AD7912/AD79221 are 10-bit and 12-bit， high speed， low power， 2-channel successive approximation ADCs， respectively. The parts operate from a single 2.35 V to 5.25 V power supply and feature throughput rates of up to 1 MSPS. The parts contain a low noise， wide bandwidth track-and-hold amplifier， which can handle input frequencies in excess of 6 MHz. The conversion process and data acquisition are controlled using CS and the serial clock， allowing the devices to interface with microprocessors or DSPs. The conversion rate is determined by the SCLK signal. The input signal is sampled on the falling edge of CS and the conversion is also initiated at this point. The channel to be converted is selected through the DIN pin， and the mode of operation is controlled by CS. The serial data stream from the DOUT pin has a channel identifier bit and mode identifier bit， which provide information about the converted channel and the current mode of operation.