The STMicroelectronics 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.

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.)