45V input ceiling and 500mA output — where this LDO fits
The LT3066EDE-3.3#PBF is a single-output positive linear regulator from Analog Devices, delivering a fixed 3.3V at up to 500mA from an input rail that can go as high as 45V. That 45V max input is the spec that sets it apart from garden-variety 5.5V or 6V LDOs — it survives 24V industrial rails with margin, handles 12V automotive transients without an external pre-regulator, and still regulates cleanly when the input sags.
71dB PSRR and 0.51V dropout — the real-world numbers
PSRR is 71dB at 120Hz — that's the rectified line-frequency ripple from a full-wave bridge. In a 24V industrial supply with 100mV of 120Hz ripple on the bulk cap, this LDO knocks it down to about 28µV at the output, which keeps sensitive analog rails clean without a second-stage LC filter. The 0.51V maximum dropout at 500mA means you need at least 3.81V on the input to hold 3.3V regulation at full load — plan the input cap and trace resistance accordingly. Quiescent current is 125µA typical, and the maximum supply current (including the pass-element drive) is 25mA. That 125µA Iq is low enough for always-on rails in battery-backed systems but not ultra-low-power — for sub-10µA standby look elsewhere in the LT306x family.
Protection features that matter on a crowded board
The protection set includes over-current, over-temperature, and reverse polarity — the reverse-polarity clamp is uncommon in linear regulators and saves an external Schottky diode when the input can be mis-wired. Control features (current limit, enable, power good, soft start) give the system designer sequencing and fault reporting without extra discretes.
Active production — no end-of-life pressure on this BOM line
ROHS3 compliant per the manufacturer's declaration.