4 1/2 Digit ADC with Multiplexed BCD Outputs

Please check latest availability status for a specific part variant.


The Maxim ICL7135 is a high precision monolithic 41/2 digit A/D converter. Dual slope conversion reliability is combined with ±1 in 20,000 count accuracy and a 2.0000V full scale capability. It features high impedance differential inputs, nearly ideal differential linearity, true ratiometric operation, auto zero and auto-polarity. The multiplexed BCD outputs and digit drivers provide easy interface to external display drivers like the Maxim ICM7211A. The only other external components needed to make precision DVM/DPMs are a reference and a clock. For more complex systems the BCD outputs are enhanced by Active-Low STROBE, OVERRANGE, UNDERRANGE, RUN/Active-Low HOLD and BUSY lines providing easy interface to microprocessors and UARTs. This interfacing capability makes the ICL7135 an ideal device for use in microprocessor based data acquisition and control systems.

The ICL7135 has auto-zero accuracy better than 10µV, zero drift of 0.5µV/°C, input bias current of 10pA max. and rollover error of less than 1 count.

ICL7135: Typical Operating Circuit ICL7135: Typical Operating Circuit Enlarge+

Key Features

  • Improved 2nd Source (See our “Maxim Advantage™” Page 3)
  • ±20,000 Count Resolution
  • Guaranteed ±1 Count accuracy
  • Over-range, under-range signals for auto-range capability
  • Easy interface to UARTs and µPs
  • TTL compatible, Multiplexed BCD outputs
  • True differential input. Zero reading guaranteed for 0 volt Input
  • True polarity at zero for precise null detection
  • Monolithic CMOS Design


  • Current
  • Material Thickness
  • Pressure
  • Resistance
  • Speed
  • Temperature
  • Voltage
  • Weight

See parametric specs for Display-Oriented ADCs (27)

Part NumberResolution
Data BusDiff/S.E. InputExternal VREF
External VREF
Bipolar VIN
minmaxmaxSee Notes
ICL7135 20000
Diff. Only-552
$10.02 @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.
Request Reliability Report for: ICL7135 
Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C   Material Composition  

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.

Quality Management System >
Environmental Management System >


Related Resources