STWD100 Watchdog timer circuit Datasheet - production data Description The STWD100 watchdog timer circuits are self- contained devices which prevent system failures that are caused by certain types of hardware errors (such as, non-responding peripherals and bus contention) or software errors (such as a bad code jump and a code stuck in loop). The STWD100 watchdog timer has an input, WDI, and an output, WDO . The input is used to Features clear the internal watchdog timer periodically Current consumption 13 A typ. within the specified timeout period, t . While the wd Available watchdog timeout periods are system is operating correctly, it periodically 3.4 ms, 6.3 ms, 102 ms, and 1.6 s toggles the watchdog input, WDI. If the system Chip enable input fails, the watchdog timer is not reset, a system alert is generated and the watchdog output, Open drain or push-pull WDO output WDO , is asserted. Operating temperature range: 40 to 125 C Packages: SOT23-5 and SC70-5 The STWD100 circuit also has an enable pin, (SOT323-5) EN , which can enable or disable the watchdog ESD performance HBM: 2000 V functionality. The EN pin is connected to the CDM: 1000 V internal pull-down resistor. The device is enabled Automotive qualified if the EN pin is left floating. Applications Telecommunications Alarm systems Industrial equipment Networking Medical equipment UPS (uninterruptible power supply) Automotive January 2017 DocID14134 Rev 11 1/20 www.st.com This is information on a product in full production. Contents STWD100 Contents 1 Package pin connections and pin description table ..................... 3 2 Functional description .................................................................... 4 3 Operation ......................................................................................... 5 3.1 Watchdog input (WDI) ....................................................................... 5 3.2 Watchdog output ( WDO ) ................................................................ 5 3.3 Chip enable input ( EN ) ................................................................... 6 3.4 Applications information .................................................................... 7 4 Watchdog timing ............................................................................. 8 5 Maximum ratings ........................................................................... 11 6 DC and AC parameters ................................................................. 12 7 Package information ..................................................................... 14 7.1 SOT23-5 package information ........................................................ 15 7.2 SC70-5 (or SOT323-5) package information ................................... 16 8 Ordering information ..................................................................... 17 9 Revision history ............................................................................ 19 2/20 DocID14134 Rev 11