Hello,
the current datasheet of the TPS3305 does not mention the case when the WDI pin is left floating: the TPS3305 watchdog is disabled.
The old datasheet SLVS198A − DECEMBER 1998 − REVISED DECEMBER 2002, page 3, has this information:
The TPS3305-xx devices integrate a watchdog timer that is periodically triggered by a positive or negative
transition of WDI. When the supervising system fails to retrigger the watchdog circuit within the time-out interval,
t t(out) = 1.6 s, RESET becomes active for the time period t d . This event also reinitializes the watchdog timer.
Leaving WDI unconnected disables the watchdog.
(This datasheet revision is easy to find on the web)
I could not find this information in the new datasheet.
Can I assume that the TPS3305 will continue to work as described in SLVS198A?
I use the part in a new design and it will be floating at startup until the software runs (>1.6s).
Also there still is the incorrect schematic as described here:
https://e2e.ti.com/support/power_management/svs_and_sequencers/f/212/t/99072
The schematic in the old datasheet is correct.
