Automotive buck regulator for 5.5A point-of-load rails
The Texas Instruments LMS3655MQURNLRQ1 is a non-synchronous step-down buck regulator rated for 5.5 A continuous output, built for automotive-grade power rails that need to survive underhood temperatures. Its 3.9 V to 36 V input range covers cold-crank dips on a nominal 12 V bus and handles load-dump transients without an external clamp, while the adjustable output from 1 V to 20 V gives flexibility for logic, sensor, or actuator supplies. Switching at 400 kHz, it balances inductor size against efficiency — the fixed frequency keeps the EMI filter design predictable across the load range.
Thermal and package realities for the rework bench
The wettable flank makes optical solder-joint inspection possible after reflow, which helps on automotive lines where X-ray isn't always practical. Will it survive the hot air? Yes — the QFN body is small enough that a preheat plate at 150 °C and a focused nozzle at 260 °C lifts the part clean without cooking adjacent passives. Surface-mount with wettable flank means the side pads are plated so the fillet wicks up the edge — a visual check confirms the joint is good, no need to X-ray every pad.
Sourcing and compliance baseline
That certification is the authority signal for underhood or chassis-mounted ECUs. Supplied in Tape & Reel (TR) or Cut Tape (CT) — the reel quantity suits production runs; cut tape works for prototypes or small-batch builds.