4.1V fixed LDO for high-voltage automotive rails
The MCP1792T-4102H/CB is a fixed 4.1V output LDO from Microchip's automotive-grade series, rated for 100 mA continuous output. What sets it apart is the 55 V maximum input voltage — it regulates cleanly from a 12 V or 24 V battery bus without needing a pre-regulator, and it survives load-dump events that would overstress a standard 6 V input LDO. The PSRR starts at 80 dB at 100 Hz and rolls to 55 dB at 100 kHz — that 25 dB drop across the audio band matters if you are powering a sensor or CAN transceiver from a noisy DC-DC rail. At 100 kHz the rejection is still 55 dB, which is enough to keep switching ripple off the output.
Dropout and quiescent current at temperature
Maximum dropout is 1.2 V at the full 100 mA load — so the input must stay above 5.3 V to hold regulation. The quiescent current is 45 µA typical, rising to 150 µA max including the enable pin draw. That Iq is low enough for always-on modules in a vehicle, but the 1.2 V dropout means you cannot run it from a 5 V rail with margin; it needs a 6 V or higher input. Protection features include over-current, over-temperature, short-circuit, and under-voltage lockout — the UVLO threshold is not specified in the brief, but the block shuts the pass element off below the minimum input. The enable pin lets a supervisor or ignition signal gate the output.
Active production with AEC-Q100 traceability
The AEC-Q100 qualification (grade 0 implied by the 150 °C rating) means the part has passed the full automotive stress suite — high-temperature operating life, temperature cycling, and HBM/CDM ESD. The SOT-23A-3 package is a standard three-lead footprint shared with many LDOs, so board layout is straightforward. ROHS3 compliant.