Keystone Electronics 7812

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 ms 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
Independent 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 6 2.5%
Operating Supply Range: +2.7 V to +5.5 V
Specifications at 2.7 V–3.6 V and 5 V 6 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