The AD7811 and AD7812 are high speed， low power， 10-bit A/D converters that operate from a single 2.7 V to 5.5 V supply. The devices contain a 2.3 μs successive approximation A/D converter， an on-chip track/hold amplifier， a 2.5 V on-chip reference and a high speed serial interface that is compatible with the serial interfaces of most DSPs （Digital Signal Processors） and microcontrollers. The user also has the option of using an external reference by connecting it to the VREF pin and setting the EXTREF bit in the control register. The VREF pin may be tied to VDD. At slower throughput rates the power-down mode may be used to automatically power down between conversions. The control registers of the AD7811 and AD7812 allow the input channels to be configured as single-ended or pseudo differential. The control register also features a software convert start and a software power-down. Two of these devices can share the same serial bus and may be individually addressed in a multipackage application by hardwiring the device address pin. The AD7811 is available in a small， 16-lead 0.3“ wide， plastic dual-in-line package （mini-DIP）， in a 16-lead 0.15” wide， Small Outline IC （SOIC） and in a 16-lead， Thin Shrink Small Outline Package （TSSOP）。 The AD7812 is available in a small， 20-lead 0.3“ wide， plastic dual-in-line package （mini-DIP）， in a 20-lead， Small Outline IC （SOIC） and in a 20-lead， Thin Shrink Small Outline Package （TSSOP）.