500 mA, 40 V input, 150°C junction — the under-hood LDO
The TPS7B8750QKVURQ1R2 is a single-output positive LDO from Texas Instruments, fixed at 5 V, delivering 500 mA continuous. The 40 V maximum input covers a 12 V battery's full transient range — cold-crank dips and load-dump spikes both stay inside the abs-max envelope without an external clamp. Maximum dropout is 0.575 V at the full 500 mA load, so a 5.575 V input rail is the floor for regulation at rated current. The 26 µA quiescent current keeps the draw negligible in always-on ECU domains. AEC-Q100 Grade 0 qualification means the junction temperature range spans -40°C to 150°C — this is the engine-bay band. An exhaust-adjacent module or transmission controller that sees 125°C ambient still has 25°C of margin before the thermal shutdown threshold.
PSRR and protection — what the 70 dB figure buys you
PSRR is 70 dB at 1 kHz — that attenuates a 100 mV ripple on the input rail to roughly 30 µV at the output. Above the crossover frequency the rejection rolls off, so a switching pre-regulator running at 400 kHz needs its output capacitor to handle the high-frequency attenuation before the LDO. Integrated protection covers over-current, over-temperature, and under-voltage lockout. The Power Good flag asserts when the output is within regulation — a pull-up resistor to the output rail lets the downstream ECU monitor the rail status without an additional comparator.
TO-252-5 DPak — board integration
The TO-252-5 (DPak) package has four leads plus a tab — the tab is the thermal pad and is tied to ground.