The AD7866 is a dual 12-bit high speed， low power， successive approximation ADC. The part operates from a single 2.7 V to 5.25 V power supply and features throughput rates up to 1 MSPS. The device contains two ADCs， each preceded by a low noise， wide bandwidth track-and-hold amplifier that can handle input frequencies in excess of 10 MHz. The conversion process and data acquisition are controlled using standard control inputs， allowing easy interfacing to microprocessors or DSPs. The input signal is sampled on the falling edge of CS; conversion is also initiated at this point. The conversion time is determined by the SCLK frequency. There are no pipelined delays associated with the part. The AD7866 uses advanced design techniques to achieve very low power dissipation at high throughput rates. With 3 V supplies and 1 MSPS throughput rate， the part consumes a maximum of 3.8 mA. With 5 V supplies and 1 MSPS， the current consumption is a maximum of 4.8 mA. The part also offers flexible power/throughput rate management when operating in sleep mode. The analog input range for the part can be selected to be a 0 V to VREF range or a 2 : VREF range with either straight binary or twos complement output coding. The AD7866 has an on-chip 2.5 V reference that can be overdriven if an external reference is preferred. Each on-board ADC can also be supplied with a separate individual external reference. The AD7866 is available in a 20-lead thin shrink small outline （TSSOP） package.