This Power Supply Monitor-Memory Protector Circuit Diagram detects low-voltage supply conditions, down to 0.6 V. Dl sets the trip point of the circuit. The circuit is useful to protect memory circuits from accidental writes in the event of power-supply low-voltage conditions, which cause other circuits to turn off, etc. Response time is about 700 ns. R6 provides some hysteresis to ensure clean transitions.
Power Supply Monitor-Memory Protector Circuit Diagram