800V breakdown, 7 W ceiling — off-line switcher for auxiliary rails
The VIPER012HSTR is an offline switching regulator from STMicroelectronics integrating an 800V avalanche-rugged MOSFET and a PWM controller in a single 10-SSOP package. It supports buck, buck-boost, and flyback topologies, making it a flexible building block for auxiliary power supplies in appliances, industrial controls, and smart meters. Rated output power is 7 W — this is the continuous ceiling in a typical flyback configuration at minimum input. For a buck converter running from a 400V DC bus, the practical load is lower due to duty-cycle limits (80% max).
120 kHz switching, built-in protection — BOM savings
The 120 kHz fixed switching frequency keeps the transformer or inductor small while staying below the conducted-EMI quasi-peak limit in most off-line designs without heavy filtering. On-chip fault protection covers current limiting, over-temperature, over-voltage, and short-circuit — four functions that would otherwise require external sense resistors, comparators, and a supervisor IC. The start-up voltage is 8 V, and the supply range (Vcc) spans 4.5 V to 30 V, accommodating a wide auxiliary winding voltage.
Active production, 10-SSOP package — sourcing posture
STMicroelectronics lists the VIPER012HSTR as Active. ROHS3 compliant.