20 W flyback with 800 V avalanche-rugged MOSFET
The STMicroelectronics VIPER25LN is a monolithic flyback switching regulator from the VIPer™ plus family, integrating a 800 V avalanche-rugged power MOSFET and PWM controller in a 7-lead DIP package. It delivers up to 20 W of isolated output power, making it a fit for auxiliary supplies, appliance power stages, and industrial control converters where through-hole assembly is preferred.
136 kHz switching — transformer sizing and EMI
The 136 kHz switching frequency reduces transformer core volume compared to lower-frequency designs while keeping switching losses manageable at 20 W. The 8.5 V to 23.5 V Vcc range accommodates universal input with a 14 V startup threshold.
The VIPER25LN is officially obsolete per STMicroelectronics' lifecycle status.
Through-hole 7-DIP — rework-friendly package
The 7-lead DIP (0.300 inch body) is a through-hole package that reworks cleanly under a soldering iron or hot-air station — no risk of lifting pads like a QFN. The 150 °C junction temperature rating means the part can tolerate brief soldering heat without damage, though the junction-to-ambient thermal resistance of the DIP package limits continuous dissipation without a heatsink or adequate copper area.