MAX6467

19-2523; Rev 0; 7/02 Microprocessor Supervisory Reset Circuits with Edge-Triggered, One-Shot Manual Reset General Description The MAX6467/MAX6468 microprocessor (µP) supervisory circuits monitor single power-supply voltages from +1.8V to +5.0V and assert a reset if the supply voltage drops below its preset threshold. An edge-triggered, one-shot manual reset function ensures that the µP enters the reset mode for a fixed timeout period only, even in the event of a continuously asserted manual reset. The MAX6467/MAX6468 significantly improve system reliability compared to traditional manual reset supervisory circuits. A variety of factory-trimmed threshold options accommodate different supply voltages and tolerances, eliminating external components. The factory-set thresholds range from +1.575V to +4.625V to monitor +5.0V, +3.3V, +3.0V, +2.5V, and +1.8V supplies with various tolerances. Reset timeout periods of 150ms (min) and 1200ms (min) are available to accommodate different µP platforms. A single, active-low RESET output asserts when VCC drops below its threshold or if the edge-triggered MR asserts low. RESET remains low for the reset timeout period after VCC rises above its threshold and for a fixed, one-shot timeout period after a manual reset input falling edge. RESET remains valid as long as VCC remains above +1V. Open-drain (MAX6467) and push-pull (MAX6468) output options provide additional flexibility in the system design. The MAX6467/MAX6468 are offered in the space-...