Features: • Low cost, simple functionality
• PC parallel printer port interface standard
• Support resolution up to 23 binary bits + signpolarity bit
• Easy to use to acquire up to 23 bit linearityand noise performance
• Integration time can be set by the user
• Easy user evaluation and setting ofconversion parameters
• Low power dissipation - 4 mA typicalincluding crystal oscillator
• On-chip Crystal Oscillator Circuit
• Two way asynchronous handstransfer
• Conversion speed versus resolution trade-off
• Power down (sleep mode) control input topower down to 2 mA
• Chip Select control input
• High impedance DV, DOUT and SCLKwhen chip not selected
• Single 3 V to 5 V power supplyApplication• Operate in conjunction with ALD500/ALD500RPrecision analog signal processors
• High accuracy DC voltage measurement functions
• Portable battery operated instruments
• PC-based software control or stand-alone operation (withoutother processors or PC)
• Serial digital output interface to other microprocessors ormicrocontrollersPinout
Specificationsly voltage,V+................................................................................. +7.0V
Differential input voltage range........... ......................-0.3V to V+ +0.3V
Power dissipation
Operating temperature range PD, SD package ....600 mW 0 to +70
Storage temperature range...................................... ....-65 to +150
Lead temperature, 10 seconds ...................................................+260 DescriptionThe ALD500/ALD500R is a digital controller designed to interface to the ALD500or ALD500R integrating dual slope analog processors as a chip set forbuilding a precision analog-to-digital converter. With the ALD500/ALD500R, together with a few externalcapacitors and resistors, aprecision Analog to Digital converter with auto zero and auto-polaritycan be implemented.
The ALD500/ALD500R can operate in either a stand-alone mode or in anexternal microprocessor control mode. In the stand-alone mode, the product can either making continuous measurements or a singlemeasurement. Under external microprocessor control, the product can directly interact with a PC under PC software control via a standardparallel printer port with no other components, or it canalso communicatewith other microcontrollers serially.
The ALD500/ALD500R analog processors consist of on-chip digitalcontrol circuitry to accept control inputs, integrating buffer amplifiers,analog switches, and voltage comparators. It functions in four operatingmodes, or phases, namely auto zero, integrate, deintegrate, andintegrator zero phases. At the end of a conversion, the comparatoroutput goes from high to low when theintegrator crosses zero duringdeintegration. ALD500/ALD500R analog processors also provide direct logicinterface to CMOS logic families.
ALD521D Data Sheet
