What this supervisor does and who specifies it
The TPS3801J25DCKR is a single-channel voltage supervisor from Texas Instruments that monitors a 2.25V threshold rail and asserts a reset signal when the supply drops below that level. It is a Simple Reset/Power-On Reset type with an Active Low, Push-Pull output — meaning the reset pin goes low when the monitored voltage falls below threshold and stays low for at least 120ms after the supply recovers. This part is typically specified by hardware engineers designing processor, FPGA, or ASIC power sequencing where a clean, timed reset pulse is needed to guarantee the logic starts from a known state.
The 2.25V threshold is set to monitor a 2.5V or 3.3V rail — if that rail droops below 2.25V, the supervisor pulls the reset output low.
Housed in a 5-lead SC-70-5 (SOT-353) package, the footprint is about 2.0mm x 2.1mm — small enough to fit under a mezzanine connector or alongside a BGA without crowding the decoupling caps.