The VIPER28HDTR is a monolithic offline flyback switcher from ST's VIPer™ plus family, rated for 16 W output with an 800 V breakdown internal switch. That 800 V rating is the headroom you need for universal AC input (85–265 VAC) without derating through the line surges — a common gotcha in 230 V designs where 650 V parts run tight. Switching at 115 kHz, it lands in the sweet spot between transformer size and EMI filter complexity. The 80% duty cycle ceiling gives the controller room to regulate through deep brownout conditions.
Protection set and supply range
Built-in fault protection covers current limiting, over-temperature, over-voltage, and short circuit — four guards that reduce the external component count in a typical charger or auxiliary supply. The VCC range of 8.5 V to 23.5 V and a 14 V start-up threshold mean it powers up cleanly from a bulk cap without an auxiliary winding pre-bias.
The 16-SOIC package is a standard footprint, and the Tape & Reel option (Cut Tape also available) matches pick-and-place feeders without a changeover.