The TPS54540B-Q1 device is a 42-V, 5-A, step-down regulator with an integrated high-side MOSFET. The device survives load-dump pulses up to 65 V per ISO 7637. Current mode control provides simple external compensation and flexible component selection. A low-ripple pulse-skip mode reduces the no load supply current to 146 µA. Shutdown supply current is reduced to 2 µA when the enable pin is pulled low. Undervoltage lockout is internally set at 4.3 V but can be increased using an external resistor divider at the enable pin. The output voltage start-up ramp is internally controlled to provide a controlled start-up and eliminate overshoot. A wide adjustable frequency range allows either efficiency or external component size to be optimized. Output current is limited cycle-by-cycle. Frequency foldback and thermal shutdown protect internal and external components during an overload condition. The TPS54540B-Q1 is available in an 8-pin thermally-enhanced HSOP PowerPAD package.