100 W flyback in a PowerSO-10 — what it takes
The STMicroelectronics VIPER100ASPTR-E is a monolithic flyback switching regulator from the VIPER™ series, integrating the power MOSFET and control logic in a single PowerSO-10 Exposed Bottom Pad package. It delivers up to 100 W in an isolated flyback topology — a dense power stage for offline AC-DC converters, auxiliary supplies, and industrial bias rails. The controller runs from an 8 V to 15 V supply rail, with an 11 V startup threshold.
Switching frequency and control features
Switching frequency goes up to 200 kHz, letting the designer shrink the transformer and output filter compared to a 65 kHz flyback. The trade-off is higher switching losses in the MOSFET — the thermal pad on the PowerSO-10 needs a good copper pour and vias to the ground plane to keep the junction temperature under control at full load. Control features include an enable pin, frequency control, and soft start — enough flexibility to synchronise with an external clock or implement burst-mode at light load. Fault protection covers current limiting and over-temperature shutdown, both built-in without external sense resistors.