1A LDO — the dropout headroom and the 2.5V rail
The TPS72525KTTRG3 is a single-output positive LDO from Texas Instruments, fixed at 2.5 V, rated for 1 A continuous. The 225 µA quiescent current (325 µA max supply) keeps the idle draw low enough for always-on rails in battery-backed or energy-harvesting designs.
60 dB PSRR — what it rejects and where it stops
Power-supply rejection is 60 dB at 1 kHz — that attenuates a 100 mV ripple on the input to 100 µV at the output at that frequency. Above the regulator's control-loop bandwidth, PSRR rolls off; a switching converter running at 500 kHz will see much less rejection, so post-filtering or a second-stage LC filter may be needed if the load is noise-sensitive (analog front-end, ADC reference). The 60 dB figure is typical, not guaranteed minimum — derate for temperature and load current per the datasheet curves.
Protection set — over-current, over-temp, reverse polarity, UVLO
The TPS72525KTTRG3 integrates over-current limiting, thermal shutdown, reverse-polarity protection, and under-voltage lockout (UVLO). The UVLO prevents the output from turning on until the input rail is high enough to keep the pass device in regulation — avoids glitched start-up on a slowly rising supply. Reverse-polarity protection clamps the input if the rail is accidentally reversed, which matters in field-service or battery-cable scenarios where the connector is not keyed.
DDPAK/TO-263-5 — thermal and footprint reality
The TO-263-6 (D²Pak, 5 leads plus tab) package is a surface-mount power package with an exposed metal tab on the bottom. The tab is the thermal path — it must be soldered to a copper pad on the PCB, and the pad should connect to a via array or a copper plane to pull heat away. At 1 A with a 0.28 V dropout, the power dissipated is 280 mW; with the tab at 25°C ambient, the junction stays well below 125°C, but in a 85°C enclosure the thermal budget shrinks. The Enable and Reset control pins let the system sequence the 2.5 V rail and hold the downstream load in reset until the output is stable.