IMP692A

IMP690A , 692A , 802L/M, 805L POWER MANAGEMENT µP Power Supply Supervisor with Battery Backup Switch The IMP690A/IMP692A/IMP802L/IMP802M/IMP805L simplify power supply monitoring and control in microprocessor systems. Each circuit implements four functions: Reset control, watchdog monitoring, batterybackup switching and power-failure monitoring. In addition to microprocessor reset under powerup and power-down conditions, these devices provide battery-backup switching to maintain control in powerloss and brown-out situations. Additional monitoring capabilities can provide an early warning of unregulated power-supply loss before the voltage regulator drops out. The important features of these four functions are: a) 1.6 second watchdog timer to keep microprocessor responsive b) c) 4.40V or 4.65V VCC threshold for microprocessor reset at power-up and power-down SPDT (single-pole, double-throw) PMOS switch connects backup power to RAM if VCC fails Key Features x Design improvement over Maxim MAX690A/692A/802L/802M/805L — 70% lower current than Maxim: 100µA maximum — RESET Operation to 1.1V x Two precision supply-voltage monitor options — 4.65V (IMP690A/802L/805L) — 4.40V (IMP692A/802M) x Battery-backup power switch on-chip x Watchdog timer: 1.6 second timeout x Power failure/low battery detection x Short-circuit protection and thermal limiting x Small 8-pin SO package x No external components x Specified over full temperature range d) 1.25V threshold detector for power loss or g...