MAX807N

` Precision 4.675V (MAX807L), 4.425V (MAX807M), or 4.575V (MAX807N) Voltage Monitoring
` 200ms Power-OK/Reset Time Delay
` RESET and RESET Outputs
` Independent Watchdog Timer
` 1A Standby Current
` Power Switching 250mA in V_CC Mode 20mA in Battery-Backup Mode
` On-Board Gating of Chip-Enable Signals; 2ns CE Gate Propagation Delay
` MaxCap® and SuperCap® Compatible
` Voltage Monitor for Power Fail
` Backup-Battery Monitor
` Guaranteed RESET Valid to V<sub>CC</sub> = 1V
` ±1.5% Low-Line Threshold Accuracy 52mV above Reset Threshold

The MAX807N microprocessor (P) supervisory circuit reduces the complexity and number of components needed to monitor power-supply and battery-control functions in P systems. A 70A supply current makes the MAX807N ideal for use in portable equipment, while a 2ns chip-enable propagation delay and 250mA output current capability (20mA in battery-backup mode) make it suitable for larger, higher-performance equipment.

The MAX807N comes in 16-pin DIP, SO, and TSSOP packages, and provides the following functions:

• P reset. The active-low RESET output is asserted during power-up, power-down, and brownout conditions, and is guaranteed to be in the correct state for V_CC down to 1V.
• Active-high RESET output.
• Manual-reset input.
• Two-stage power-fail warning. A separate low-line comparator compares VCC to a threshold 52mV above the reset threshold. This low-line comparator is more accurate than those in previous P supervisors.
• Backup-battery switchover for CMOS RAM, real-time clocks, Ps, or other low-power logic.
• Write protection of CMOS RAM or EEPROM.
• 2.275V threshold detector provides for power-fail warning and low-battery detection, or monitors a power supply other than +5V.
• BATT OK status flag indicates that the backup-battery  voltage is above +2.275V.
• Watchdog-fault output-asserted if the watchdog input has not been toggled within a preset timeout period.