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VIPER12A / VIPER12AS Off-Line SMPS Primary IC — SOP-8, 730V, Induction Cooker (5-Pack)
VIPER12A / VIPER12AS Off-Line SMPS Primary IC SOP-8, 730V, Induction Cooker (5-Pack)
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VIPER12A / VIPER12AS Off-Line SMPS Primary IC — SOP-8, 730V, 12W (5-Pack)
The VIPER12A and VIPER12AS are off-line flyback SMPS primary ICs from STMicroelectronics, integrating a PWM controller and a 730V avalanche-rated power MOSFET in a single SOP-8 package. Designed for low-power offline switching power supplies up to 12W, they are widely used in induction cooker auxiliary power supplies, USB chargers, LED drivers, and standby power circuits. The VIPER12AS adds a soft-start function for reduced inrush current.
Key Specifications
| Parameter | Value |
|---|---|
| Package | SOP-8 (SMD) |
| Integrated MOSFET | 730V avalanche-rated |
| Max Output Power | 12W (continuous, open-frame) |
| Switching Frequency | 60kHz (fixed) |
| Startup Current | 25μA (ultra-low) |
| Operating Mode | Current-mode PWM + burst mode at light load |
| Protection | OCP, OVP, OTP, auto-restart |
| VCC Range | 9–38V |
| Quantity | 5 pieces |
VIPER12A vs VIPER12AS
| Feature | VIPER12A | VIPER12AS |
|---|---|---|
| Soft-Start | No | Yes (internal) |
| Inrush Current | Standard | Reduced |
| Best For | Standard charger/adapter repair | Induction cooker, sensitive loads |
Why Choose VIPER12A / VIPER12AS?
- Integrated 730V MOSFET — no external power transistor needed, reduces BOM and PCB area
- 25μA startup current — ultra-low standby power for energy efficiency compliance
- Burst mode at light load — improves efficiency under no-load and standby conditions
- Full protection suite — OCP/OVP/OTP with auto-restart prevents damage under fault conditions
- STMicroelectronics — industry-standard part with comprehensive application notes (AN2450, AN2458)
Compatible With / Common Use Cases
- Induction cooker auxiliary PSU: 5V/12V standby supply for control board (most common repair use)
- USB charger / phone adapter: 5V/2A offline flyback design
- LED driver power supply: Isolated constant-voltage LED supply
- Industrial standby supply: 5V/12V auxiliary rail for PLC and industrial controllers
Frequently Asked Questions
Q: What is the difference between VIPER12A and VIPER22A?
A: Both are off-line flyback ICs with integrated 730V MOSFET. VIPER12A is rated for up to 12W output; VIPER22A supports up to 22W. Use VIPER22A for higher-power chargers and adapters above 12W.
Q: Can I use VIPER12AS as a direct replacement for VIPER12A?
A: Yes — VIPER12AS is pin-compatible with VIPER12A and adds internal soft-start. It is a drop-in upgrade that reduces inrush current stress on the transformer and output capacitors.
Q: What reference design should I follow for an induction cooker repair?
A: Refer to STMicroelectronics Application Note AN2450 (“VIPERx2A family design guidelines”) and AN2458 for the induction cooker auxiliary supply reference design. The typical circuit uses VIPER12A with a flyback transformer, TL431 feedback, and PC817 optocoupler.
Package Contents
- 5× VIPER12A / VIPER12AS Off-Line SMPS Primary IC (SOP-8)
