MAX791

Microprocessor Supervisory Circuit

Full-Function µP Supervisory Circuit


Please check latest availability status for a specific part variant.

Description

The MAX791 microprocessor (µP) supervisory circuit reduces the complexity and number of components needed to monitor power-supply and battery-control functions in µP systems. The 50µA supply current makes the MAX791 ideal for use in portable equipment, while the 6ns chip-enable propagation delay and 250mA output capability (25mA in battery-backup mode) make it suitable for larger, higher-performance equipment.

The MAX791 comes in 16-pin DIP and narrow SO packages and provides the following functions:
  1. µP reset-RESET-bar output is asserted during power-up, power-down, and brownout conditions, and is guaranteed to be in the correct state for VCC down to 1V, even with no battery in the circuit.
  2. Manual-reset input.
  3. A 1.25V threshold detector provides for power-fail warning and low-battery detection, or monitors a power supply other than +5V.
  4. Two-stage power-fail warning-a separate low-line comparator compares VCC to a threshold 150mV above the reset threshold.
  5. Backup-battery switchover for CMOS RAM, real-time clocks, µPs, or other low-power logic.
  6. Software monitoring of backup-battery voltage.
  7. A watchdog-fault output is asserted if the watchdog input has not been toggled within either a preset or an adjustable timeout period.
  8. Write protection of CMOS RAM or EEPROM.
  9. Pulsed watchdog output, to give advance warning of impending WDO-bar assertion caused by watchdog timeout.
MAX791: Typical Operating Circuit MAX791: Typical Operating Circuit Enlarge+

Key Features

  • Precision 4.65V Voltage Monitoring
  • 200ms Power-OK/Reset Time Delay
  • Independent Watchdog Timer-Preset or Adjustable
  • 1µA Standby Current
  • Power Switching
    • 250mA Output in VCC Mode
    • 25mA Output in Battery-Backup Mode
  • On-Board Gating of Chip-Enable Signals
    • Memory Write-Cycle Completion
    • 6ns CE Gate Propagation Delay
  • MaxCap™ or SuperCap™ Compatible
  • Voltage Monitor for Power-Fail or Low-Battery Warning
  • Backup-Battery Monitor
  • Guaranteed RESET-bar Valid to VCC = 1V

Applications/Uses

  • Computers: Desktop, Workstation, Server
  • Controllers
  • Critical µP Monitoring
  • Intelligent Instruments
  • Portable Battery-Powered Equipment
Part NumberReset Thresh.
(V)
Reset OutICC
(µA)
Oper. Temp.
(°C)
Package/PinsBudgetary
Price
maxSee Notes
MAX791 3.3 to 5.5
Active Low
Push-Pull
150
-55 to +125
-40 to +85
0 to +70
CDIP/16
PDIP/16
SOIC (N)/16
TSSOP/16
$5.27 @1k
See All Battery Backup Circuits (82)
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.

Quality and Environmental Data

Product Reliability Reports: MAX791.pdf 
Lead-Free Package Tin (Sn) Whisker Reports

CAD Symbols and Footprints

  • MAX791CPE
  • MAX791CPE+
  • MAX791CSE+
  • MAX791CSE+T
  • MAX791CUE
  • MAX791CUE+
  • MAX791CUE+T
  • MAX791CUE-T
  • MAX791EJE
  • MAX791EPE
  • MAX791EPE+
  • MAX791ESE+
  • MAX791ESE+T
  • MAX791EUE
  • MAX791EUE+
  • MAX791EUE+T
  • MAX791EUE-T
  • MAX791MJE
  • Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C  

    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 >

     
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    Temperature:

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