Watchdog supervisor for automotive and industrial systems
The STMicroelectronics STWD100NPWY3F is a single-channel watchdog supervisor IC in a SOT-23-5 package, designed to monitor microcontroller activity and assert a system reset if the watchdog service pulse is missed. It provides an active-low, open-drain reset output, which allows direct connection to MCU reset pins or wired-OR configurations with other fault signals.
2.3 ms minimum reset timeout — what it means for system response
The STWD100NPWY3F has a minimum reset timeout of 2.3 ms, which is significantly shorter than the 140 ms minimum offered by general-purpose reset ICs like the STM706 or STM809. This fast timeout suits applications where the MCU must recover quickly from a fault — for example, in safety-critical sensor loops or actuator control where a 140 ms pause would exceed the system's fault-reaction budget. It also reduces the risk of nuisance resets in systems that service the watchdog at a high rate.