5A fixed 3.3V rail with 0.5V dropout headroom
The TPS75533KC is a 5A fixed 3.3V output LDO regulator from Texas Instruments, in a through-hole TO-220-5 package.
60dB PSRR at 100Hz means the regulator attenuates 100Hz ripple from a rectified mains supply by a factor of 1000 — a 1Vpp ripple on the input becomes 1mVpp on the 3.3V output. This is the dominant noise frequency in linear supplies fed from a full-wave rectifier; the rejection drops at higher frequencies, so upstream filtering is still needed if the input carries switching-regulator hash above a few kHz. The protection block includes over-current, over-temperature, reverse polarity, and under-voltage lockout (UVLO). The UVLO prevents the pass element from operating in the linear region during input brownout, which would otherwise dump the full dropout voltage across the pass transistor at 5A and exceed the SOA. Reverse polarity protection blocks a negative input without an external series diode, saving 0.4V to 0.6V of headroom that a Schottky would consume. Quiescent current is 200 µA — the regulator's own draw is negligible against the 5A load, but in an always-on rail that powers a sleep-mode microcontroller, the 200 µA floor sets the battery drain when the load is in deep sleep. Enable pin allows the regulator to be shut down entirely, dropping Iq to near zero.
No stock-holding claim; we quote per RFQ with lot traceability where available.