The TPS3305-25D is a multi-voltage supervisor from Texas Instruments that monitors two supply rails simultaneously — thresholds set at 2.25 V and 2.93 V. The 140 ms minimum reset timeout holds the system in reset long enough for the supplies to stabilise after a brown-out or power-up event.
Threshold selection and reset timing for processor supervision
The 2.93 V threshold monitors a 3.3 V rail with roughly 11 % undervoltage margin — typical for FPGA core or I/O bank supervision. The 2.25 V threshold suits a 2.5 V rail (10 % margin). The 140 ms reset timeout is a fixed minimum; no external capacitor sets the delay, which simplifies BOM but means the designer cannot stretch the timeout for slow-start supplies. The push-pull output drives both active-high and active-low signals from the same package, so a single TPS3305-25D can interface to processors that expect opposite reset polarities without extra logic.