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