VIPER38LD

Overview

The VIPER38LD is an offline switch from the VIPerPlus family, designed as a high-voltage AC/DC converter. It integrates an 800 V avalanche-rugged power MOSFET with a PWM current-mode controller in a 16-SO package. The device operates at a fixed frequency of 60 kHz and supports a flyback topology. It functions within a supply voltage range of 8.5 V to 23.5 V, with a startup voltage of 14 V. The component delivers up to 20 W of output power and features an 80% maximum duty cycle. It includes embedded high-voltage startup and sense FETs, allowing for minimal external component usage.

Feature Summary

• Integrates an 800 V rugged power MOSFET with PWM current-mode control for ultra-wide input voltage ranges.
• Features dual-level overcurrent protection (I_Dlim and I_DMAX) to prevent transformer saturation and secondary diode short-circuits.
• Includes an adjustable extra power timer (EPT) to sustain overload conditions temporarily without shutting down.
• Provides comprehensive protection including output overvoltage, thermal shutdown with hysteresis, and automatic restart after fault removal.

Applications

• Offline AC/DC power supplies
• Flyback converter designs
• High-voltage converter applications

Procurement Notes

Verify the specific suffix 'L' indicates the 60 kHz operating frequency variant when sourcing replacements. Confirm the 16-SOIC package dimensions match the target footprint. Ensure the design accounts for the 800 V breakdown rating of the integrated MOSFET. Check RoHS compliance status if required by local regulations. Validate that the 20 W power rating aligns with the system's peak load requirements.

Selection Notes

Select this component for applications requiring a fixed 60 kHz switching frequency. The integrated HV startup reduces bill of materials count compared to solutions requiring external bias windings. The jittered frequency feature aids in meeting EMI standards. Consider the thermal performance limits when designing for the upper end of the -40°C to +150°C junction temperature range.

Part Context

This part belongs to the VIPerPlus series, which combines high-voltage power technology with intelligent digital control. The series is designed to meet stringent energy-saving standards through low no-load consumption and burst mode operation. The VIPER38LD specifically targets cost-sensitive, high-reliability power conversion systems where compact size and robust protection are critical.

Replacement Considerations

VIPER38LDTR is a verified equivalent part number offering identical electrical specifications and functionality. Both parts share the same core architecture and protection features. The primary difference lies in the packaging format, with TR indicating tape and reel delivery suitable for automated assembly processes.

FAQ

What is the switching frequency of the VIPER38LD?

The VIPER38LD operates at a fixed frequency of 60 kHz. This distinguishes it from the 'H' type variants in the same family, which operate at 115 kHz.

How does the Extra Power Timer (EPT) function?

The EPT allows the IC to sustain overload conditions for a few seconds by blanking the overload current. This prevents immediate shutdown during transient overload events, enhancing system reliability.

What protections are included in the VIPER38LD?

The device includes dual-level overcurrent protection, output overvoltage protection with a digital noise filter, short-circuit protection, and thermal shutdown with hysteresis. It also features automatic restart after a fault condition is removed.