Three-rail watchdog for mixed-voltage boards
The TPS3307-25DGN is a three-channel voltage supervisor from TI that keeps an eye on your 2.25 V, 2.93 V, and one adjustable rail — common in DSP, FPGA, or mixed-signal boards where the core, I/O, and analog supplies all need their own reset threshold. It asserts both active-high and active-low reset outputs (push-pull, totem pole) when any monitored voltage drops below its threshold, and holds reset for a minimum of 140 ms after all rails come back up — enough for most processors to finish their power-on sequence.
Thresholds and the exposed-pad footprint
The three monitored thresholds are set internally at 2.25 V and 2.93 V, with the third channel adjustable via an external resistor divider — handy when you need to supervise a 1.8 V or 3.0 V rail that doesn't match a standard fixed threshold. Package is an 8-pin HVSSOP with an exposed pad (the 8-MSOP / 8-TSSOP variant with thermal slug). Surface-mount only — no through-hole option, so plan for reflow or hand-solder with a hot-air station if you're doing a field repair.