PSRR across the band — the noise-rejection story
The MAX8902AATA/V+T delivers 92 dB PSRR at 5 kHz, dropping to 62 dB at 100 kHz. That 30 dB roll-off above the switching-regulator crossover means upstream buck converter ripple at 2 MHz is attenuated by roughly 40 dB — enough to keep a 3.3 V analog rail clean for a 16-bit ADC front-end without a post-filter.
Dropout and headroom — what 120 mV means at 500 mA
Maximum dropout is 120 mV at the full 500 mA output. If the input rail is 3.3 V and the output is set to 3.0 V, the headroom is 300 mV — 180 mV above the dropout ceiling, so the output stays in regulation across load steps and temperature. Below that margin the LDO enters dropout and PSRR collapses.
AEC-Q100 Grade 1 — where it sits in the vehicle
That covers the under-hood and engine-bay temperature envelope — an ECU seeing 105°C on a summer grade still has 20°C of margin before the silicon junction exceeds the rated limit.
Protection set and quiescent current
Over-temperature, reverse polarity, short-circuit, and soft-start protection are integrated — no external supervisor or current-limit resistor needed. Quiescent current is 120 µA typical, supply current maxes at 160 µA, so in a battery-backed module that sleeps most of the time the LDO's own draw is negligible.