Low-Power, 12-Bit Sampling ADC with Internal Reference and Power-Down

See MAX129X Family for New Designs

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The MAX191 is a monolithic, CMOS, 12-bit analog-to-digital converter (ADC) featuring differential inputs, track/hold (T/H), internal voltage reference, internal or external clock, and parallel or serial µP interface. The MAX191 has a 7.5µs conversion time, a 2µs acquisition time, and a guaranteed 100ksps sample rate.

The MAX191 operates from a single +5V supply or from dual ±5V supplies, allowing ground-referenced bipolar input signals. The device features a logic power-down input, which reduces the 3mA VDD supply current to 50µA max, including the internal-reference current.

Decoupling capacitors are the only external components needed for the power supply and reference. This ADC operates with either an external reference, or an internal reference that features an adjustment input for trimming system gain errors.

The MAX191 provides three interface modes: two 8-bit parallel modes, and a serial interface mode that is compatible with SPI™, QSPI™, and MICROWIRE™ serial-interface standards.
MAX191: Functional Diagram MAX191: Functional Diagram Enlarge+

Key Features

  • 12-Bit Resolution, 1/2 LSB Linearity
  • +5V or ±5V Operation
  • Built-In Track/Hold
  • Internal Reference with Adjustment Capability
  • Low Power:
    • 3mA Operating Mode
    • 20µA Power-Down Mode
  • 100ksps Tested Sampling Rate
  • Serial and 8-Bit Parallel µP Interface
  • 24-Pin Narrow DIP and Wide SO Packages


  • Automated Test Equipment (ATE)
  • Battery-Powered Data Logging
  • Data Acquisition
  • Digital Signal Processing (DSP)
  • Electromechanical Systems
  • High-Accuracy Process Control
  • PC Pen Digitizers
  • Telecommunications

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

Part NumberResolution
Input ChannelsConv. Rate
ADC ArchitectureData BusDiff/S.E. InputInternal VREF
External VREF
External VREF
Unipolar VIN
ADCmaxnominalminmaxmaxSee Notes
MAX191 121100SAR
Diff. Only4.0962.554.096-801
SOIC (W)/24
$13.16 @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.

MAX191EVKIT: Evaluation System/Evaluation Kit for the MAX191
Product Reliability Reports: MAX191.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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