STMicroelectronics VIPER20A-E

Overview

VIPER20A-E from STMicroelectronics is a 700 V, 0.5 A integrated primary-side SMPS controller combining a current-mode PWM controller and a vertical high-voltage Power MOSFET in a single PENTAWATT HV package. It delivers up to 10 W in universal-input offline power supplies, features adjustable 90–110 kHz switching frequency, internal 13 V VDD regulation, and burst-mode operation enabling <1 W standby consumption compliant with the German Blue Angel standard.

For engineers reviewing the VIPER20A-E datasheet, VIPER20A-E pinout, VIPER20A-E application, or VIPER20A-E equivalent, key selection considerations include its integrated start-up current source, programmable peak current limit (0.5–0.9 A), thermal shutdown at 140–190 °C, and compatibility with both primary- and secondary-side regulation topologies without external bias windings.

Technical Context

The VIPER20A-E implements current-mode control using an internal transconductance error amplifier (Gm = 1.1–1.9 mA/V) and a dedicated current-sense comparator with 250 ns blanking time and 350–1200 ns minimum on-time. Its oscillator supports external RT/CT programming and synchronization via the OSC pin, maintaining stable 90–110 kHz operation across VDD = 9–15 V.

It integrates a 700 V vertical Power MOSFET with RDS(on) = 15.5–32 Ω (TJ = 25–100 °C), undervoltage lockout with 3 V hysteresis (VDDon = 11–12 V, VDDoff = 7.5–9 V), and overtemperature protection with 40 °C hysteresis. Standby mode is autonomously triggered when VCOMP falls below 0.5 V, forcing zero-duty-cycle burst operation.

Key Specifications

Pinout & Package

PENTAWATT HV (15.4 × 10.0 mm, 5-pin, heat sink tab on backside) - thermally optimized for through-hole mounting with direct PCB copper pour contact to drain-source thermal path.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ICE2QS03G and LNK304P, the VIPER20A-E uniquely combines integrated HV start-up, programmable burst-mode entry, and OSC synchronization-enabling simpler, more robust, and globally compliant offline power designs up to 10 W.

Availability

VIPER20A-E is available at Aetrix Electronics and suitable for smart home adapters, industrial sensor transmitters, white goods control boards, and medical auxiliary supplies requiring stable component supply, long-term lifecycle support, and Blue Angel-compliant standby performance.

Supply support for VIPER20A-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, designing and manufacturing microcontrollers, power ICs, sensors, and automotive-grade components.

The VIPer™ family targets cost-sensitive, high-reliability offline SMPS applications-integrating HV MOSFETs and controllers to replace discrete solutions in sub-25 W power supplies.

FAQ

What is the minimum recommended VDD capacitor value for reliable startup?

The minimum VDD capacitor (C_VDD) must satisfy C_VDD > (I_DD1 × t_SS) / V_DDhyst, where I_DD1 = 13 mA (at 100 kHz), t_SS is worst-case startup time (typically 50–100 ms), and V_DDhyst = 2.4 V min. For t_SS = 80 ms, C_VDD > 430 µF. A 470 µF/25 V electrolytic capacitor is commonly used with low-ESR characteristics.

Can VIPER20A-E operate with primary-side regulation only-no optocoupler?

Yes. The device supports primary-side regulation by connecting a resistive divider from the auxiliary winding to the VDD pin. When VDD rises above 13.4 V, the internal regulator clamps it, and the error amplifier's output (COMP) adjusts duty cycle to maintain regulation-eliminating optocoupler, TL431, and associated compensation components.

How does the blanking time affect safe operation at high line voltage?

The fixed 250–360 ns blanking time prevents false current-sense triggering from parasitic ringing during MOSFET turn-on. At 265 V_AC input, primary di/dt is highest; insufficient blanking would cause premature switch-off and instability. This built-in delay ensures robust operation without external RC snubbers on the sense resistor.

Is external slope compensation required for continuous conduction mode (CCM)?

Yes, when operating above 50% duty cycle in CCM, external slope compensation is required to prevent subharmonic oscillation. A sawtooth waveform injected into the COMP pin-derived from the OSC pin via a resistor and transistor-adds artificial ramp to the current-sense signal, restoring loop stability per IEEE 1547 guidelines.