What this offline flyback switcher brings to a 22 W supply
The VIPER35HDTR is an offline flyback switcher from STMicroelectronics that integrates the controller and a 800 V avalanche-rugged power MOSFET in a single 16-SOIC package. Switching at 225 kHz lets you shrink the flyback transformer core compared to a 65 kHz design, which directly reduces the overall converter footprint and bill-of-materials height. The supply voltage range of 8.5 V to 23.5 V on Vcc gives flexibility for both self-supplied and externally biased configurations, while the 14 V startup threshold ensures clean turn-on even with a slow-rising bulk capacitor.
Protection set and thermal headroom
On-chip fault protection covers current limiting, over-temperature, over-voltage, and short-circuit conditions — meaning you can often omit external sense resistors or a separate OVP clamp, simplifying the BOM.
Package, mounting, and sourcing posture
It is supplied on tape and reel (cut tape available) in the 16-SOIC (0.154", 3.90 mm width) body — a hand-solderable footprint that also suits reflow assembly. Because this is an active, single-sourced ST part, the procurement path is through authorized distribution.