4-Pin µP Voltage Monitors with Manual Reset Input

4-Pin SOT Reset ICs with Manual Reset

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The MAX811/MAX812 are low-power microprocessor (µP) supervisory circuits used to monitor power supplies in µP and digital systems. They provide excellent circuit reliability and low cost by eliminating external components and adjustments when used with 5V-powered or 3V-powered circuits. The MAX811/MAX812 also provide a debounced manual reset input.

These devices perform a single function: They assert a reset signal whenever the VCC supply voltage falls below a preset threshold, keeping it asserted for at least 140ms after VCC has risen above the reset threshold. The only difference between the two devices is that the MAX811 has an active-low RESET output (which is guaranteed to be in the correct state for VCC down to 1V), while the MAX812 has an active-high RESET output. The reset comparator is designed to ignore fast transients on VCC. Reset thresholds are available for operation with a variety of supply voltages.

Low supply current makes the MAX811/MAX812 ideal for use in portable equipment. The devices come in a 4-pin SOT143 package.
MAX811, MAX811L, MAX811M, MAX811R, MAX811S, MAX811T, MAX812, MAX812L, MAX812M, MAX812R, MAX812S, MAX812T: Typical Operating Circuit MAX811, MAX811L, MAX811M, MAX811R, MAX811S, MAX811T, MAX812, MAX812L, MAX812M, MAX812R, MAX812S, MAX812T: Typical Operating Circuit Enlarge+

Key Features

  • Integrated Voltage Monitor Increases System Robustness with Added Manual Reset
    • Precision Monitoring of 3V, 3.3V, and 5V Power-Supply Voltages
    • 140ms Min Power-On-Reset Pulse Width
      • - Active-Low RESET Output (MAX811), RESET Output (MAX812)
    • Guaranteed Over Temperature
    • Guaranteed Active-Low RESET Valid to VCC = 1V (MAX811)
    • Power-Supply Transient Immunity
  • Saves Board Space
    • No External Components
    • 4-Pin SOT143 Package
  • Low Power Consumption Simplifies Power-Supply Requirements
    • 6µA Supply Current


  • Computers: Desktop, Workstation, Server
  • Controllers
  • Critical µP and µC Power Monitoring
  • Intelligent Instruments
  • Portable Battery-Powered Equipment

See parametric specs for Supervisors (1 Monitored Voltage) (252)

Part NumberReset Thresh.
Reset OuttRESETWatchdog FeatureSupervisor FeaturesReset Thresh. Accur.
min@ +25°CmaxSee Notes
2.5 to 3.3
3.3 to 5.5
Active Low
85ms to 300msNo WatchdogManual Reset1.515
$1.60 @1k
Active High
$1.51 @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.

Tools & Models

  • MAX811S IBIS Model
  • Product Reliability Reports: MAX811.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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