Processor Supervisor 4.65V 4.65V 16-Pin SOIC N

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: 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. Manual-reset input. A 1.25V threshold detector provides for power-fail warning and low-battery detection, or monitors a power supply other than +5V. Two-stage power-fail warning-a separate low-line comparator compares VCC to a threshold 150mV above the reset threshold. Backup-battery switchover for CMOS RAM, real-time clocks, µPs, or other low-power logic. Software monitoring of backup-battery voltage. A watchdog-fault output is asserted if the watchdog input has not been toggled within either a preset or an adjustable timeout period. Write protection of CMOS RAM or EEPROM. Pulsed watchdog output, to give advance warning of impending WDO-bar assertion caused by watchdog timeout.

• 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 V_CC 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 V_CC = 1V