ZHCSFP2B October 2016 – September 2021 TPS3850
PRODUCTION DATA
In this application, the window watchdog timing options are based on the PWM signal that is provided to the TPS3850. A window watchdog setting must be chosen such that the falling edge of the PWM signal always falls within the window. A nominal window must be designed with tWDL(max) less than 5 ms and tWDU(min) greater than 5 ms. There are several options that satisfy this window option. An external capacitor can be placed on the CWD pin and calculated to have a sufficient window. Another option is to use one of the factory-programmed timing options. An additional advantage of choosing one of the factory-programmed options is the ability to reduce the number of components required, thus reducing overall BOM cost. Leaving the CWD pin unconnected (NC) with SET0 = 0 and SET1 = 1 produces a tWDL(max) of 2.22 ms and a tWDU(min) of 23.375 ms; see Figure 8-10.