Two-voltage supervisor for mixed-rail systems
The Texas Instruments TPS3305-33DG4 is a multi-voltage supervisor that monitors two independent supply rails — one at 2.93V and the other at 4.55V — and asserts both an active-high and an active-low reset signal when either rail drops below its threshold. The push-pull, totem-pole output drives the reset line directly without an external pull-up resistor, saving a component on the BOM.
140 ms reset timeout — what it buys the processor
The minimum reset timeout of 140 ms gives the power supply time to stabilise and the processor time to complete its internal reset sequence before the supervisor releases the reset line. For a typical microcontroller or DSP, that window covers the power-on ramp and the oscillator start-up period without the need for an external delay capacitor.