The MIC1832 is a multifunction circuit which monitors microprocessor activity, external reset and power supplies in microprocessor based systems. The circuit functions include a watchdog timer, 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 (2.55V or 2.88V). 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 within the watchdog timeout period. The watchdog timeout period is selectable with a nominal periods of 150, 600, or 1200 milliseconds.
The MIC1832 is a multifunction circuit designed to monitor microprocessor activity, external reset, and power supplies in microprocessor-based systems. Key features include a watchdog timer with selectable timeout periods, a precision supply voltage monitor, and a manual pushbutton reset input. The device ensures system stability by asserting a reset signal when power supply conditions are out of tolerance or if the watchdog timer times out.
| Supply Voltage Range | 3 to 5.5 V |
|---|---|
| Supply Current (Typical) | < 181A |
| Watchdog Timeout Periods | 150ms, 600ms, or 1200ms |
| Reset Time Delay | 250ms minimum |
The watchdog timeout period is selectable with nominal periods of 150, 600, or 1200 milliseconds.
The threshold is selected by the TOL pin: connecting it to ground selects 5% of Vcc, and connecting it to Vcc selects 10% of Vcc.
The PBRST input requires a pulse of 20ms or greater to guarantee a reset.