GENERAL DESCRIPTION

The ALD521D is a digital controller designed to interface to the ALD500 or ALD500R integrating dual slope analog processors as a chip set for building a precision analog-to-digital converter. With the ALD521D and ALD500R, together with a few external capacitors and resistors, a precision Analog to Digital converter with auto zero and auto-polarity can be implemented.

FEATURES AND BENEFITS

• Low cost, simple functionality

• PC parallel printer port interface standard

• Support resolution up to 23 binary bits + sign polarity bit

• Easy to use to acquire up to 23 bit linearity and noise performance

• Integration time can be set by the user

• Easy user evaluation and setting of conversion parameters

• Low power dissipation - 4 mA typical including crystal oscillator

• On-chip Crystal Oscillator Circuit

• Two way asynchronous handshake data transfer

• Conversion speed versus resolution trade-off

• Power down (sleep mode) control input to power down to 2 µA

• Chip Select control input

• High impedance DV, DOUTand SCLK when chip not selected

• Single 3 V to 5 V power supply

APPLICATIONS

• Operate in conjunction with ALD500/ALD500R Precision analog signal processors

• High accuracy DC voltage measurement functions

• Portable battery operated instruments

• PC-based software control or stand-alone operation (without other processors or PC)

• Serial digital output interface to other microprocessors or microcontrollers