Fixed 5V rail for automotive ECUs — 2.5A continuous, 36V input ceiling
The LM53625LQURNLRQ1 is a synchronous step-down regulator from Texas Instruments, part of the Automotive, AEC-Q100 series. It delivers a fixed 5V output at 2.5A continuous from an input range of 3.9V to 36V. The 3.9V minimum input covers a deeply discharged automotive battery during cold-crank; the 36V maximum handles load-dump transients without an external clamp, provided the upstream TVS is sized for the energy. Switching at 2.1 MHz, the regulator uses a small inductor — typically 2.2 µH to 4.7 µH — which shrinks the PCB footprint, but the fast edges demand tight layout of the input loop and the SW node to keep radiated emissions within CISPR 25 Class 5 limits.
Junction temperature range and synchronous rectification
Output is fixed at 5V with positive polarity; the single output channel is configured as a step-down (buck) topology.
Package and board-fit — 22-VQFN with wettable flank
Housed in a 22-VQFN-HR package measuring 5 mm × 4 mm, the part uses a wettable flank terminal finish. This allows automated optical inspection (AOI) of the solder fillet on the side of the package — a requirement for automotive production lines that cannot rely on bottom-only X-ray inspection. The surface-mount package with wettable flank is specified for the Automotive, AEC-Q100 series, supporting the PPAP documentation package that tier-one ECU programs require. Available in Tape & Reel (TR) and Cut Tape (CT) formats for both high-volume pick-and-place and prototype builds.