LD1117S33CTR

LD1117S33CTR is an STMicroelectronics fixed 3.3 V low-dropout linear regulator in a SOT-223 package, delivering up to 800 mA with a typical dropout voltage of 1 V and ±1% output accuracy at 25 °C, from inputs up to 15 V — a board-level 3.3 V rail for microcontrollers, logic and mixed-signal loads fed from 5 V or unregulated adapters. ST lists this exact order code as Active on its eStore CPN page. Selection advice: the S33 code is the fixed 3.3 V SOT-223 version and CTR is its tape-and-reel ordering form; the adjustable and other fixed-voltage LD1117 variants share the footprint but not the output, so match the full code to the rail. Dropout is the design check: with 1 V typical dropout, a nominal 5 V input is comfortable, but a sagging rail at full 800 mA load is not — and the SOT-223 tab is the heatsink, so board copper area, not the headline current, sets the practical limit in continuous service. Parameters verified against STMicroelectronics documentation.