Two-rail watchdog for mixed-voltage boards
The Texas Instruments TPS3306-25D is a dual-voltage supervisor designed to monitor two independent supply rails — one at 2.25V and the other at 2.93V — and assert a common active-low reset signal when either rail drops below its threshold. The open-drain output allows wire-ORing with other reset sources or level-shifting to the processor's reset input via an external pull-up resistor.
70 ms reset timeout — what it buys the system
The reset timeout is rated at 70 ms minimum. That is long enough to cover most processor power-on reset hold requirements and to debounce supply glitches that last a few milliseconds. If your processor specifies a reset pulse width shorter than 70 ms, this part meets it with margin — the timeout starts after the monitored rails rise above the threshold, so the processor stays in reset until both supplies are stable and the timer expires.