The STMicroelectronics VIPER53SP-E is an offline flyback switching regulator from the VIPER™ series, integrating a 620 V avalanche-rugged power MOSFET and current-mode PWM controller in a single PowerSO-10 package with an exposed bottom pad for thermal management. It delivers up to 65 W in a flyback topology with output isolation, making it a fit for auxiliary power supplies in industrial equipment, appliance SMPS, and AC-DC converters where board space and component count need to be held down.
The 65 W power rating sets the design ceiling for a flyback stage. The 620 V breakdown voltage on the internal MOSFET gives headroom for universal AC input with a reasonable derating margin. Switching frequency runs up to 300 kHz.
Built-in fault protections reduce external parts
The VIPER53SP-E packs current limiting, overload, over-temperature, and short-circuit protection on-chip. That means you can drop the external sense resistor and OTP thermistor from the BOM for many designs — the chip handles hiccup-mode restart on its own. The soft-start and frequency-control features let you tune the startup ramp and spread-spectrum behavior if needed, though the base part runs fine with the default internal settings for a standard 65 W flyback.
Surface-mount PowerSO-10 with an exposed bottom pad. The pad needs a thermal via array to the ground plane — the 65 W output at full load will pull the junction temperature up fast if the PCB copper area is skimped. Supply range is 8.4 V to 19 V on Vcc with an 11.5 V startup threshold.
For dual-sourcing or a pin-compatible second source within the VIPER family, the base number VIPER53 shares the same footprint and controller architecture, but verify the specific variant suffix (SP-E vs SP) against your BOM — the -E denotes the lead-free version.