12-Bit A/D Converter with 3-State Binary Outputs

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The ICL7109 is a monolithic 12 bit A/D converter designed for easy interface with microprocessors and UARTs. The 12 bit binary plus polarity and over-range outputs can be directly interfaced to a microprocessor bus. In this mode the ICL7109 is controlled by the microprocessor through the chip select and tow byte enable inputs. For remote data logging applications the ICL7109 outputs are easily converted to a UART handshake mode, working with industry standard UARTs to provide serial data transmission.

This device offers high accuracy by lowering rollover error to less than 1 count and zero reading drift to less than 1μV/ °C. In many data acquisition systems the ICL7109 is an attractive, low cost, one-per-channel alternative to analog multiplexing due to its low power consumption and input bias current.

Maxim has added a zero-integrator phase to the ICL7109, eliminating overrange hangover, "crosstalk" and hysteresis effects. Maxim has also increased the current sourcing capabilities of the ICL7109, enabling it to rapidly drive the large capacitances often found on microprocessor busses.
ICL7109: Typical Operating Circuit ICL7109: Typical Operating Circuit Enlarge+

Key Features

  • Improved 2nd Source!
  • Zero Integrator Phase for Fast Overload Recovery
  • Hysteresis and "Crosstalk" Eliminated
  • Enhanced Bus Driving Capability
  • Byte Organized Three-state Outputs
  • UART Handshake Mode for Serial Interfacing
  • True Differential Input and Reference
  • Up to 30 Conversions per Second
  • Significantly Improved ESD Protection
  • Monolithic, Low Power CMOS Design


  • Current
  • Flow
  • Power
  • Pressure
  • Resistance
  • Speed
  • Temperature
  • Voltage
  • Weight

See parametric specs for Display-Oriented ADCs (27)

Part NumberResolution
Conv. Rate
Data BusDiff/S.E. InputInternal VREF
External VREF
External VREF
Bipolar VIN
maxnominalminmaxmaxSee Notes
ICL7109 40960.03
Diff. Only-2.8-553.5
$5.72 @1k

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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Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

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