Buck controller with wide input and high temp ceiling
The LM25085ASDE/NOPB is a non-synchronous step-down (buck) controller from Texas Instruments, switching at up to 1 MHz and accepting a 4.5 V to 42 V supply rail. It drives an external transistor (no synchronous rectifier), so the bill-of-materials includes a Schottky catch diode. The 100% duty-cycle capability means the output can run at the input voltage minus the drop across the external pass element — useful in battery-powered systems where the input sags close to the setpoint.
The small 3x3 mm footprint leaves room for the catch diode and inductor on a compact layout. No clock sync input means the switching frequency is set by a single resistor — a clean, low-component-count design for point-of-load regulators.