ADM708

Data Sheet Low Cost Microprocessor Supervisory Circuits ADM705/ADM706/ADM707/ADM708 FEATURES Guaranteed RESET valid with VCC = 1 V 190 μA quiescent current Precision supply voltage monitor 4.65 V (ADM705/ADM707) 4.40 V (ADM706/ADM708) 200 ms reset pulse width Debounced TTL/CMOS manual reset input (MR) Independent watchdog timer (ADM705/ADM706) 1.60 sec timeout (ADM705/ADM706) Active high reset output (ADM707/ADM708) Voltage monitor for power fail or low battery warning Superior upgrade for MAX705 to MAX708 APPLICATIONS Microprocessor systems Computers Controllers Intelligent instruments Critical microprocessor supply monitoring GENERAL DESCRIPTION The ADM705/ADM706/ADM707/ADM708 microprocessor supervisory circuits are suitable for monitoring 5 V power supplies/batteries and microprocessor activity. The ADM705/ADM706 provide power-supply monitoring circuitry that generate a reset output during power-up, powerdown, and brownout conditions. The reset output remains operational with VCC as low as 1 V. Independent watchdog monitoring circuitry is also provided. This is activated if the watchdog input has not been toggled within 1.60 sec. In addition, there is a 1.25 V threshold detector to warn of power failures, to detect low battery conditions, or to monitor an additional power supply. An active low, debounced manual reset input (MR) is also included. 00088-001 FUNCTIONAL BLOCK DIAGRAMS WATCHDOG INPUT (WDI) WATCHDOG TRANSITION DETECTOR WATCHDOG TIMER WATCHDOG OUTPUT (WDO...