The MIC1232 is a multifunction circuit which monitors microprocessor activity, external reset and power supplies in microprocessor based systems. The circuit functions include a watchdog time, power supply monitor, microprocessor reset, and manual pushbutton reset input.

The power supply line is monitored with a comparator and an internal voltage reference. /RST is forced low when an out-of-tolerance condition exists and remains asserted for at least 250ms after VCC rises above the threshold voltage (4.5V or 4.75V). The /RST pin will remain logic low with VCC as low as 1.4V.

The Watchdog input (/ST) monitors µP activity and will assert /RST if no µP activity has occurred with in the watchdog timeout period. The watchdog timeout period is selectable with nominal period of 150, 600, 1200 milliseconds.

   Power OK/Reset time delay, 250ms min.

   Watchdog timer, 150ms, 600ms, or 1.2s typical

   Precision supply voltage monitor, select between 5% or 10% of supply voltage

   Available in 8-pin surface mount (SO)

   Debounced External reset input

   Low supply current, <18µA typical