Flyback controller in a 7-lead SOIC
The Texas Instruments UCC28710D is an offline flyback controller designed for isolated AC-DC and DC-DC converter stages. It operates from a 9 V to 35 V supply rail (Vcc/Vdd) and delivers a switching frequency that spans 680 Hz to 100 kHz, giving the transformer designer a wide window to optimize for size or efficiency. The tube delivery suits medium-volume production runs where tape-and-reel is not required.
Isolated topology with integrated protection
The UCC28710D implements a flyback topology with output isolation — the primary-side controller drives an external switch (no internal FET), so the power stage rating is set by the choice of MOSFET and transformer. This architecture is standard for off-line supplies in chargers, adapters, and auxiliary bias rails where galvanic isolation is required for safety. Fault protection includes current limiting and over-voltage detection on the primary side, which reduces the component count for the protection loop. The 21 V startup threshold ensures the controller begins switching once the bulk capacitor charges above that level, then operates down to the 9 V undervoltage lockout.
Temperature grade and operating range
The wide supply range (9-35 V) allows it to ride through line dips on a 24 V industrial bus or a 12 V automotive rail without dropping out.
The part is RoHS3 compliant, which satisfies the current EU and China RoHS requirements without exemption claims.