GENERAL DESCRIPTION

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.

FEATURES

10-Bit ADC with 2.3 μs Conversion Time

The AD7811 has Four Single-Ended Inputs that

Can Be Configured as Three Pseudo Differential

Inputs with Respect to a Common, or as Two Inde pendent Pseudo Differential Channels

The AD7812 has Eight Single-Ended Inputs that Can

Be Configured as Seven Pseudo Differential Inputs

with Respect to a Common, or as Four Independent

Pseudo Differential Channels

Onboard Track and Hold

Onboard Reference 2.5 V ±2.5

Operating Supply Range: 2.7 V to 5.5 V

Specifications at 2.7 V–3.6 V and 5 V ±10

DSP-/Microcontroller-Compatible Serial Interface

High Speed Sampling and Automatic Power-Down Modes

Package Address Pin on the AD7811 and AD7812 Allows

Sharing of the Serial Bus in Multipackage Applications

Input Signal Range: 0 V to VREF

Reference Input Range: 1.2 V to VDD

Qualified for Automotive Applications