STMicroelectronics VIPER28HD

Overview

VIPER28HD from STMicroelectronics is a high-voltage AC-DC converter IC integrating an 800 V avalanche-rugged power MOSFET, current-mode PWM controller, and embedded HV startup circuit. It delivers up to 12 W continuous output in open-frame designs at 50 °C ambient, supports dual-frequency operation (60 kHz or 115 kHz), and achieves 30 mW no-load consumption at 230 Vac - enabling compliance with stringent energy-saving standards in auxiliary power supplies.

For engineers reviewing the VIPER28HD datasheet, VIPER28HD pinout, VIPER28HD application, or VIPER28HD equivalent, key selection considerations include its adjustable dual-level overcurrent protection (IDlim = 0.8 A typ., IDMAX = 1.2 A), SO16 narrow package thermal resistance (RthJA = 105 °C/W on standard FR4), and EPT-enabled sustained overload capability for up to 2 seconds.

Technical Context

The VIPER28HD implements a current-mode PWM architecture with integrated gate driver, jittered oscillator (±4 kHz or ±8 kHz modulation depth), and dual-stage protection logic. Its power section uses an avalanche-rated 800 V N-channel MOSFET with RDS(on) = 7 Ω @ 25 °C and COSS = 40 pF, enabling robust flyback operation across 85–265 Vac input ranges.

Control functions are centralized around three critical pins: FB regulates duty cycle via bias current sourcing (IFB1 = −200 µA typ.), CONT sets cycle-by-cycle current limit or enables OVP monitoring, and EPT connects an external capacitor to extend overload tolerance. Thermal shutdown activates at TJ = 155 °C (typ.) with 30 °C hysteresis.

Key Specifications

Pinout & Package

VIPER28HD is housed in a SO16 narrow (SOIC-16) surface-mount package with exposed drain pads (pins 13–16) for enhanced thermal dissipation. The package measures 10.3 mm × 7.5 mm × 2.65 mm (max) and supports reflow soldering per JEDEC J-STD-020.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-voltage AC-DC converter applications.

Compared with VIPER28HD, ICE3BR1765J demands more external components and offers narrower protection coverage, while VIPER06XS sacrifices frequency flexibility and overload headroom - making VIPER28HD optimal for new designs targeting >10 W with enhanced reliability.

Availability

VIPER28HD is available at Aetrix Electronics and suitable for auxiliary power supplies in energy meters, home appliance standby systems, and compact AC-DC adapters requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for VIPER28HD 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 analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

VIPER28HD belongs to the VIPer Plus family of high-voltage converters engineered specifically for cost-sensitive, space-constrained AC-DC applications demanding integrated power switches, ultra-low standby power, and comprehensive fault protection.

FAQ

What is the maximum continuous output power achievable with VIPER28HD in a non-ventilated adapter?

VIPER28HD delivers 10 W continuous output in a non-ventilated enclosed adapter at 50 °C ambient, as validated in ST's typical power table. This value assumes proper PCB copper area under DRAIN pins for thermal conduction and adherence to recommended layout guidelines in AN4170. Peak power reaches 17 W for ≤2 seconds with adequate heatsinking.

How does the EPT (Extra Power Timer) function affect overload behavior?

The EPT pin accepts an external capacitor to delay shutdown during moderate overloads: a 100 nF capacitor enables ~1.5 s hold time before entering hiccup mode. During this period, the IC sustains IDlim-limited current without triggering IDMAX protection, allowing temporary surges like motor startup or firmware update loads without system interruption.

Can VIPER28HD operate with a universal 85–265 Vac input without input voltage sensing?

Yes - its 800 V avalanche-rugged drain and embedded HV startup generator enable direct connection to the rectified bulk capacitor across 85–265 Vac. No auxiliary winding or input voltage divider is needed, simplifying design and reducing component count while maintaining regulation accuracy via primary-side feedback.

What is the purpose of the N.A. pin (pin 4) in the SO16 narrow package?

Pin 4 is mechanically bonded to the controller die pad and serves as a thermal and noise-shielding path. Though not electrically functional, ST strongly recommends connecting it to GND to improve electromagnetic immunity and reduce coupling of switching noise into the control circuitry - a requirement confirmed in layout guidelines of DocID15028 Rev 6.