Watchdog timers are standalone devices that can trigger a high priority interrupt on the microcontroller or microprocessor to take an appropriate action, such as system reboot. These devices are a robust, reliable means of monitoring software code execution, or hardware failures, and require high security level of applications.

The STM6xxx supervisors are self-contained devices which provide microprocessor supervisory functions. A precision voltage reference and comparator monitors the VCC input for an out-of-tolerance condition. When an invalid VCC condition occurs, the reset output (RST) is forced low (or high in the case of RST). These devices also offer a watchdog timer (except for STM6322/6825) and/or a push-button (MR) reset input. These devices are available in a standard 5-pin SOT23 package.

Precision VCC monitoring of 5, 3.3, 3, or 2.5 V power supplies
RST outputs (active low, push-pull or open drain)
RST outputs (active high, push-pull)
Reset pulse width of 1.4 ms, 200 ms and 240 ms (typ.)
Watchdog timeout period of 1.6 s (typ.)
Manual reset input (MR)
Low supply current - 3 μA (typ.)
GuaranteedRST(RST) assertion down to VCC= 1.0 V
Operating temperature: –40 to +85 °C (industrial grade)

Microprocessor Supply Voltage Supervisory & Reset Circuits

Power supply voltage monitoring and supervisory circuits for use in desktop, laptop and notebook computers, test and measurement instruments, portable battery-powered equipment and multiple-output power supplies.

Supply Voltage Detector
Supply Voltage Supervisor
Power Supply Supervisor
Microprocessor Supervisory
Microprocessor Voltage Supervisor
Microcontroller Reset Circuit