Low-Noise, 4 1/2 Digit, Single-Chip ADC with Multiplexed LCD Drivers

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The Maxim ICL7129A/MAX7129 is a high precision monolithic 4-1/2 digit A/D converter that directly drives a multiplexed liquid crystal display. Using a novel "successive integration" technique, the ICL7129A/MAX7129 has a ±20,000 count resolution on both 2.00000V and 200.00mV ranges. It features high impedance differential inputs, excellent differential linearity, true ratiometric operation and auto polarity. The only external active component required to make precision DVM/DPMs is a reference. The overrange and underrange outputs and the 10:1 range changing input facilitate the design of autoranging systems. The ICL7129A/MAX7129 detects and flags a LOW BATTERY condition and also checks for continuity, giving a visual indication and a logic level output which can be used to generate an audible signal.

The MAX7129 has a fullscale accuracy of 0.0005%, resolution of 10µV, zero reading drift of 0.5µV/°C, an input bias of 10pA max, and a rollover error of less than 1 count. Maxim has reduced the noise of the ICL7129A to 3µV—significantly lower than the MAX7129.
ICL7129A, MAX7129: Typical Operating Circuit ICL7129A, MAX7129: Typical Operating Circuit Enlarge+

Key Features

  • ±19,999 Count Resolution
  • 10pA Max Input Bias Current (MAX7129)
  • 3µV Peak-to-Peak Noise (ICL7129A)
  • Onboard Multiplexed LCD Display Driver 4-1/2 Digits, 4 Decimal Points, 3 Annunciators
  • Instant Continuity Detector
  • Low Battery Detector and Indicator
  • Overrange/Underrange Outputs
  • Precise 10:1 Range Select
  • 10µV Resolution
  • Significantly Improved ESD Protection
  • Monolithic, Low Power CMOS Design
  • Eliminates Need for Compensation Capacitor

See parametric specs for Display-Oriented ADCs (27)

Part NumberResolution
Data BusDiff/S.E. InputInternal VREF
Unipolar VIN
nominalmaxSee Notes
ICL7129A 200007-SegmentDiff. Only-2.82
$7.36 @500
$5.61 @500

Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.
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