The AD7475/AD74951 are 12-bit， high speed， low power， successive-approximation ADCs that operate from a single 2.7 V to 5.25 V power supply with throughput rates up to 1 MSPS. They contain a low noise， wide bandwidth track-and-hold amplifier that can handle input frequencies above 1 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 conversion is initiated at this point. The conversion time is determined by the SCLK frequency. There are no pipeline delays associated with the device. The AD7475/AD7495 use advanced design techniques to achieve very low power dissipation at high throughput rates. With 3 V supplies and a 1 MSPS throughput rate， the AD7475 consumes just 1.5 mA， while the AD7495 consumes 2 mA. With 5 V supplies and 1 MSPS， the current consumption is 2.1 mA for the AD7475 and 2.6 mA for the AD7495. The analog input range for the devices is 0 V to REF IN. The 2.5 V reference for the AD7475 is applied externally to the REF IN pin， while the AD7495 has an on-board 2.5 V reference. 1 Protected by U.S. Patent No. 6，681，332