55V input LDO with 80dB PSRR
The MCP1792T-4102H/DB is a fixed-output 4.1V LDO from Microchip, rated for a 55V maximum input and 100mA output current. It targets automotive and industrial applications where a clean, regulated rail must be derived from a high-voltage, noisy bus — think 12V/24V battery systems or 48V telecom supplies that see transients well above the nominal rail.
PSRR across the audio band
Power supply rejection ratio is specified at 80dB at 100Hz, dropping to 55dB at 100kHz. This means the regulator attenuates 100Hz ripple (common in rectified mains or alternator output) by a factor of 10,000, while higher-frequency switching noise from a downstream buck converter sees about 560× attenuation. For a sensor or analog front-end powered from a shared rail, that PSRR profile determines whether the ripple couples into the signal path. Dropout voltage is 1.2V maximum at the full 100mA load, so the input must stay at least 1.2V above the 4.1V output to maintain regulation. Quiescent current is 45 µA typical, with a maximum supply current of 150 µA — low enough for always-on modules in a vehicle that draw power even when the ignition is off.
Automotive temperature grade and protection
That covers under-hood and engine-bay environments where ambient temperatures can exceed 105°C. Protection features include over-current, over-temperature, short-circuit, and under-voltage lockout (UVLO) — the regulator shuts down cleanly rather than latching or oscillating during a fault. It is ROHS3 compliant.
Package and hand-solderability
The part comes in a TO-261-4 (also known as SOT-223-3) surface-mount package. The tab is the output pin, and the three leads are gate, input, and ground. At a 1.5mm pitch and with a visible tab, this is a hand-solderable package — a fine-tip iron and some flux will do the job. No reflow oven required for a prototype or a small run.