The AD7276/AD7277/AD7278 are 12-/10-/8-bit， high speed， low power， successive approximation analog-to-digital converters （ADCs）， respectively. The parts operate from a single 2.35 V to 3.6 V power supply and feature throughput rates of up to 3 MSPS. The parts contain a low noise， wide bandwidth trackand-hold amplifier that can handle input frequencies in excess of 55 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 input signal is sampled on the falling edge of CS， and the conversion is initiated at this point. There are no pipeline delays associated with the part. The AD7276/AD7277/AD7278 use advanced design techniques to achieve very low power dissipation at high throughput rates. The reference for the part is taken internally from VDD. This allows the widest dynamic input range to the ADC; therefore， the analog input range for the part is 0 to VDD. The conversion rate is determined by the SCLK