6.5A switch in a 3x3 QFN — automotive-grade power stage
The LM5157QRTERQ1 is a current-mode boost controller with an integrated 6.5A switch, qualified to AEC-Q100 Grade 0 with a junction temperature range of -40°C to 150°C. It supports boost, flyback, and SEPIC topologies from a single 1.5V to 45V input rail, making it suitable for automotive battery-fed rails that must survive cold-crank dips and load-dump transients.
Wide input range and adjustable output up to 48V
Input voltage spans 1.5V minimum to 45V maximum — the 1.5V floor lets the part start from a single-cell Li-ion or a deeply discharged lead-acid battery, while the 45V ceiling covers 12V and 24V automotive systems with margin for load-dump clamping. Output is adjustable from 1.5V up to 48V, so a single BOM line can serve a 3.3V pre-regulator, a 12V auxiliary rail, or a 48V PoE bus. Switching frequency is programmable from 100 kHz to 2.2 MHz — the lower end suits flyback designs where transformer size is less critical, while the upper end shrinks the inductor footprint for space-constrained ECU modules. Synchronous rectification is built in, which improves efficiency at higher output currents compared to a diode-based flyback.
Active production — no last-time-buy pressure
The 16-WQFN package (3x3 mm) with exposed pad requires a thermal land pattern on the PCB for adequate heat dissipation. The exposed pad must be soldered to a copper plane; the datasheet's recommended footprint and stencil aperture are the reference for the reflow profile.