Buck controller with 42 V input ceiling
The Texas Instruments LM25085ASD/NOPB is a step-down (buck) switching controller designed for non-isolated DC-DC conversion. It drives an external N-channel MOSFET and supports a wide input voltage range from 4.5 V to 42 V. With a switching frequency up to 1 MHz, the controller allows the use of small inductors and output capacitors, shrinking the overall power supply footprint. The 100 % maximum duty cycle enables operation with very low dropout between input and output. It does not integrate synchronous rectification, so the external Schottky diode efficiency penalty at low output voltages must be budgeted.
The LM25085ASD/NOPB is supplied in an 8-WFDFN exposed pad package (8-WSON, 3 mm × 3 mm). The exposed pad on the bottom of the package must be soldered to a thermal land on the PCB to achieve the rated junction-to-ambient thermal resistance. Surface mount assembly with standard reflow profiles applies. Control features include current limit and frequency control via external resistor programming. The single output is configured as a positive transistor driver — no clock synchronization input is provided.
Active lifecycle and compliance status
The device is ROHS3 compliant, meeting the EU Restriction of Hazardous Substances directive. No UL, IEC, or AEC-Q qualification is stated on this record; for automotive-grade requirements, confirm the suffix or consult the TI documentation.