3.3V fixed rail, 100mA capacity — the fit for a clean analog supply
The LE33CD-TR is a single-output positive LDO from STMicroelectronics, delivering a fixed 3.3V at up to 100mA. The 0.5V max dropout at full load means the input rail must stay above 3.8V to maintain regulation — a 5V bus or a 3.6V Li-ion cell near end-of-discharge both provide enough headroom. Its PSRR profile — 80dB at 120Hz dropping to 60dB at 10kHz — tells you where the rejection lives: it scrubs 100/120Hz ripple from a rectified AC supply very well, but switching-regulator noise above 10kHz sees less attenuation. For a sensitive analog front-end, a post-filter LC stage ahead of this LDO is worth the board space.
Industrial temperature range and protection set
The 18V absolute-max input gives margin against 12V bus transients without an external clamp. Built-in over-current and over-temperature protection means the part folds back or shuts down before damaging itself — useful when the load is a shorted bypass cap or the ambient spikes above 125°C. The Enable pin lets a GPIO or supervisor pull the output to zero for sequenced power-up or low-power sleep.
8-SOIC footprint and tape-and-reel packaging
The tape-and-reel option (Cut Tape also available) feeds pick-and-place without a reel change.
Active lifecycle — no last-time-buy pressure
For a BOM that needs a stable 3.3V LDO through the next several production runs, this part does not force a redesign cycle.