STMicroelectronics VIPER27HDTR

Overview

VIPER27HDTR from STMicroelectronics is an off-line high-voltage PWM controller IC with integrated 800 V avalanche-rugged power MOSFET, 115 kHz switching frequency, adjustable current limit via CONT pin, and <50 mW standby power at 265 Vac - designed for auxiliary power supplies in ATX systems, DVD players, and white goods.

For engineers reviewing the VIPER27HDTR datasheet, VIPER27HDTR pinout, VIPER27HDTR application, or VIPER27HDTR equivalent, key selection criteria include its SO-16 narrow package thermal performance (R_thJA = 60 °C/W), burst-mode operation for energy compliance, brown-out protection with 0.45 V threshold, and dual-level overcurrent protection with hiccup mode recovery.

Technical Context

The VIPER27HDTR integrates a high-voltage startup generator drawing current directly from the DRAIN pin (V_{DRAIN_START} = 80 V typ.), enabling self-biased operation without external bias winding. Its oscillator employs ±8 kHz frequency jittering at 250 Hz to reduce EMI peak emissions.

It implements current-mode control with cycle-by-cycle sensing via internal SenseFET, supports adjustable overvoltage protection (VOVP = 3.0 V) strobed with 2.2 µs delay, and features hysteretic thermal shutdown at 155 °C with 30 °C hysteresis - all managed within a single monolithic die.

Key Specifications

Pinout & Package

Package: SO-16 narrow (SO16N), thermally enhanced with DRAIN pins (13–16) connected to metal frame for PCB heat dissipation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar off-line high-voltage controller applications.

Compared with ICE2QS03G and LNK306P, VIPER27HDTR provides higher voltage ruggedness (800 V), programmable current limiting, and digitally filtered OVP - making it optimal for designs requiring robust fault handling and regulatory compliance across global AC inputs.

Availability

VIPER27HDTR is available at Aetrix Electronics and suitable for ATX auxiliary power supplies, consumer DVD player SMPS, and white goods control board supplies requiring stable component supply and long-term industrial lifecycle support.

Supply support for VIPER27HDTR 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 specializing in power management, analog, and microcontroller solutions for industrial, automotive, and consumer markets.

VIPER27 belongs to ST's VIPer™ family of high-voltage offline controllers - engineered specifically for compact, low-noise, energy-compliant AC-DC conversion in cost-sensitive consumer and home appliance applications.

FAQ

What is the maximum continuous output power achievable with VIPER27HDTR in an open-frame design?

VIPER27HDTR delivers up to 12 W continuous output power in an open-frame configuration at 50 °C ambient with adequate heatsinking, as confirmed in Table 2 of the official datasheet. This assumes SO-16 narrow package mounted on a standard FR4 board with 100 mm² copper pour, leveraging its 1.5 W thermal limit and 7 Ω R_DS(on).

How does the CONT pin function in overvoltage protection mode?

The CONT pin serves dual roles: it sets the current limit via external resistor and monitors the auxiliary winding voltage during MOSFET OFF time. When V_CONT exceeds 3.0 V for four consecutive cycles (with 2.2 µs strobe delay), the IC disables switching and enters auto-restart mode - providing isolated, optocoupler-free OVP with noise immunity.

Can VIPER27HDTR operate without an auxiliary winding for VDD supply?

No - the internal HV startup generator only charges the VDD capacitor initially; sustained operation requires an auxiliary winding to maintain VDD above 8.5 V. Without it, VDD collapses after soft-start, causing shutdown. The datasheet explicitly states that CVDD must be sized to bridge the gap until auxiliary voltage stabilizes.

What is the purpose of the BR pin's hysteresis, and how is it implemented?

The BR pin implements non-latching brown-out protection with 50 mV hysteresis: device shuts down when input-derived voltage falls below 0.45 V, and only re-enables when voltage rises above 0.50 V. This prevents oscillation during marginal AC line conditions and is internally generated - no external components required beyond the input divider.