Fixed 3.3V LDO with 64dB ripple rejection
The UPC29M33AT-E1-AY: The Renesas UPC29M33AT--AY is a single-output positive LDO regulator delivering a fixed 3.3V at up to 500mA from a TO-252 surface-mount package. The 64dB PSRR at 120Hz means this part attenuates full-wave-rectified ripple from a 50/60Hz mains supply by a factor of roughly 1600 — the output sees less than 1mV of ripple for every 1V of input ripple at that frequency, making it suitable for analog front-ends and sensor supplies where clean DC matters. Input range extends to 16V maximum, with a dropout voltage of 1V at the full 500mA load — the input rail must stay at least 1V above 3.3V across the load and temperature range to keep the output in regulation.
Protection and thermal envelope
Built-in over-current and over-temperature protection means the regulator handles a momentary short or thermal overload without external crowbar circuitry — the die shuts down and auto-recovers when the fault clears. Operating temperature spans -30°C to 85°C ambient, which covers most indoor and telecom-grade enclosures but not extended automotive or under-hood ranges. Quiescent current is 3mA typical, with a maximum supply current of 20mA — the 3mA Iq is the standing draw that always flows from input to ground, so in battery-powered designs the regulator's own consumption should be factored into the sleep-mode budget.
Surface-mount assembly with standard reflow profiles for DPak packages; the tab solder joint is the primary thermal path, so the stencil aperture for the tab should be sized for full solder coverage without bridging to the adjacent pins.