65-VIN no-opto flyback converter with 100-V, 0.75-A integrated MOSFET

The LM5181 is a primary-side regulated (PSR) flyback converter with high efficiency over a wide input voltage range of 4.5 V to 65 V. The isolated output voltage is sampled from the primary-side flyback voltage, eliminating the need for an optocoupler, voltage reference, or third winding from the transformer for output voltage regulation.

The high level of integration results in a simple, reliable and high-density design with only one component crossing the isolation barrier. Boundary conduction mode (BCM) switching enables a compact magnetic solution and better than ±1.5% load and line regulation performance. An integrated 100-V power MOSFET provides output power up to 4 W with enhanced headroom for line transients.

The LM5181 flyback converter is available in a 8-pin, 4-mm × 4-mm, thermally-enhanced WSON package with 0.8-mm pin pitch.