±15-Bit, Low-Power ADC with Parallel Interface

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The MAX135 is a CMOS 15-bit, binary-output analog-to-digital converter (ADC). Multi-slope integration provides low-noise and high-resolution conversions in less time than standard integrating ADCs: The MAX135 is tested at 16 conversions per second, but operates at up to 6 times that rate. The MAX135 uses Super LSBs with data averaging to achieve 18-bit resolution.

Supply current is 125µA maximum during normal operation and only 10µA maximum in sleep mode. Low conversion noise allows tested operation at only 300mV full scale (15µV per LSB). A simple 8-bit parallel data bus and three control lines easily interface to all common microprocessors, and twos-complement output coding simplifies bipolar measurements.

High resolution and compact size make the MAX135 ideal for data loggers, numerical control systems, weight scales, data-acquisition systems, and panel meters. The MAX135 comes in 28-pin DIP and SO packages in both commercial and extended temperature grades.
MAX135: Typical Operating Circuit MAX135: Typical Operating Circuit Enlarge+

Key Features

  • 15-bit, Multi-slope Integration ADC
  • 15µV Resolution at 16 Conv/Sec
  • Low Supply Current
    • 125µA Max (Normal Operation)
    • 10µA Max (Sleep-Mode Operation)
  • ±0.005% Accuracy at 16 Conv/Sec
  • 3 Super Bits for 18-Bit Resolution
  • Low Noise—Operates at 300mV Full Scale
  • Easy µP Interface—8-Bit Parallel Data Bus
  • ±10pA Input Leakage Current
  • Small 28 pin DIP and SO packages


  • Analog-Signal Measurement: Pressure, Flow, Temperature, Voltage, Current, Resistance, Weight
  • Battery-Powered Instruments
  • Control Applications
  • Data Acquisition

See parametric specs for Precision ADCs (< 5Msps) (434)

Part NumberResolution
Input ChannelsConv. Rate
ADC ArchitectureData BusDiff/S.E. InputExternal VREF
Bipolar VIN
ADCmaxmaxmaxSee Notes
MAX135 1510.0016MSµP/8Diff. Only0.5450.3
SOIC (W)/28
$12.89 @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.
Product Reliability Reports: MAX135.pdf 
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.

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