STMicroelectronics VIPER50A-E

Overview

VIPER50A-E from STMicroelectronics is a high-voltage, current-mode PWM controller with integrated 700 V vertical power MOSFET, designed for primary-side switching in offline SMPS. It delivers up to 50 W in single-range configurations, features adjustable 90–110 kHz switching frequency, internal 13 V VDD regulation, and burst-mode operation enabling <1 W standby consumption per Blue Angel norm.

For engineers reviewing the VIPER50A-E datasheet, VIPER50A-E pinout, VIPER50A-E application, or VIPER50A-E equivalent, key selection considerations include its integrated start-up current source, 1.5 A peak current limit, 5.7 Ω R_DS(on) at 100°C, thermal shutdown at 140–170°C, and compatibility with both primary- and secondary-side regulation topologies.

Technical Context

The VIPER50A-E implements a current-mode control architecture with inner current-sense loop and outer voltage regulation loop, using a transconductance error amplifier (G_m = 1.5 mA/V) and integrated blanking time (250–360 ns) to suppress noise-induced false triggering. Its oscillator supports external synchronization via the OSC pin and maintains stable frequency (±10% variation) across VDD = 9–15 V with RT = 8.2 kΩ and CT = 2.4 nF.

Startup relies on an internal high-voltage current source connected to the DRAIN pin, automatically disabling once VDD reaches 11 V (UVLO reset threshold); undervoltage lockout re-engages below 8 V (hysteresis = 3 V). Overtemperature protection triggers at 140–170°C with 40°C hysteresis, forcing latch-off until junction temperature falls below trip-minus-hysteresis.

Key Specifications

Pinout & Package

Package: PENTAWATT HV (022Y), 5-pin through-hole package with isolated heatsink tab; thermal resistance R_thJC = 1.9 °C/W.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar SMPS primary-side controller applications.

Compared with ICE2QS03G and LNK304P, the VIPER50A-E uniquely combines integrated HV startup, programmable oscillator, and burst-mode capability-making it optimal for compact, low-standby, and certification-driven 25–50 W offline SMPS designs.

Availability

VIPER50A-E is available at Aetrix Electronics and suitable for AC-DC adapters, smart home power supplies, industrial control modules, and white goods auxiliary supplies requiring stable component supply and long-term lifecycle support.

Supply support for VIPER50A-E includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in power management, microcontrollers, and analog ICs for industrial, automotive, and consumer markets.

The VIPer™ family targets highly integrated, cost-optimized AC-DC conversion-designed specifically for offline SMPS up to 50 W with minimal external components and certified standby compliance.

FAQ

What is the minimum recommended value for the VDD bypass capacitor?

The minimum VDD capacitor must satisfy C_VDD > I_DD × t_SS / V_DDhyst, where I_DD = 16 mA (max operating current), t_SS is worst-case startup time (typically 50–100 ms), and V_DDhyst = 3 V. For t_SS = 80 ms, C_VDD ≥ 427 µF. A 470 µF/25 V low-ESR electrolytic capacitor is standard practice, placed within 5 mm of the VDD pin.

Can VIPER50A-E operate in continuous conduction mode (CCM)?

Yes-VIPER50A-E supports CCM operation with slope compensation. The datasheet Figure 21 shows a proven method: injecting sawtooth voltage from the OSC pin into the COMP node via Q1 and R/C network. This compensates subharmonic oscillation when duty cycle exceeds 50%, enabling higher power density in CCM flyback or forward converters.

How does the COMP pin function in primary versus secondary regulation?

In primary regulation, the COMP pin is tied to a resistive divider from VDD (13 V), fixing the error amplifier output and enabling fixed-output designs. In secondary regulation, the COMP pin connects to an optocoupler's phototransistor collector-allowing feedback from the secondary side to modulate duty cycle while maintaining VDD regulation at 13 V via internal reference.

Is the VIPER50A-E RoHS-compliant and halogen-free?

Yes-VIPER50A-E is manufactured in STMicroelectronics' RoHS-compliant and halogen-free PENTAWATT HV package (022Y), per specification document "Package Mechanical Data" (Section 8) and "Order Codes" (Section 9), which confirm compliance with EU Directive 2011/65/EU and JEDEC JS709B standards.