Fixed 0.9 V rail for automotive core supplies
The LP5912Q0.9DRVTQ1 is a single-output LDO from Texas Instruments, part of the Automotive AEC-Q100 series, delivering a fixed 0.9 V output at up to 500 mA. This voltage is typical for low-voltage core rails in automotive microcontrollers, FPGAs, or sensor ASICs that require a tightly regulated 0.9 V supply from a higher input bus up to 6.5 V. The 55 µA quiescent current keeps the regulator's own draw low in always-on or sleep-mode circuits, while the 600 µA maximum supply current bounds the total overhead at full load.
PSRR profile and noise rejection
Power-supply rejection ratio is specified at 65 dB at 100 Hz, rolling off to 40 dB at 100 kHz. This means the LDO attenuates low-frequency ripple from the upstream rail by a factor of roughly 1800 at 100 Hz, but the rejection drops to about 100× at 100 kHz — switching noise from a DC-DC converter above that crossover will pass through unless filtered ahead of the LDO.
Automotive qualification and protection suite
The protection block includes over-temperature shutdown, reverse-polarity immunity, and short-circuit current limiting — three failure modes common in automotive power distribution.
The exposed pad carries the ground potential and provides the primary heat path into the board. Control features include an enable pin, a power-good output for sequencing, and a soft-start ramp to limit inrush current on the output capacitor.