STMicroelectronics VIPER26HN

Overview

VIPER26HN from STMicroelectronics is a high-voltage current-mode PWM controller IC integrating an 800 V avalanche-rugged power MOSFET, embedded HV startup circuitry, and jittered 115 kHz ±8 kHz oscillator. It delivers up to 12 W in open-frame flyback designs at 50 °C ambient, achieves <30 mW no-load input power at 230 VAC, and supports adjustable current limiting via the LIM pin. It is used in auxiliary power supplies for appliances and LED drivers requiring robust overvoltage/overload protection with automatic restart.

For engineers reviewing the VIPER26HN datasheet, VIPER26HN pinout, VIPER26HN application, or VIPER26HN equivalent, key selection criteria include its 115 kHz switching frequency with ±8 kHz spread-spectrum modulation, 800 V drain-source breakdown voltage, 0.7 A typical drain current limit at 25 °C, thermal shutdown at 150 °C, and dual-package support (DIP-7 and SO16N) with validated heat dissipation paths under DRAIN pins.

Technical Context

The VIPER26HN implements a fixed-frequency current-mode PWM control architecture with integrated SenseFET-based cycle-by-cycle current sensing and a transconductance error amplifier referenced to 3.3 V on the FB pin. Its oscillator uses jittered spread-spectrum modulation at 115 kHz ±8 kHz to reduce EMI filter cost without external components.

Startup is managed by an internal high-voltage current generator sourcing −1.8 mA from the DRAIN pin until VDD reaches 12–14 V; thereafter, VDD is sustained by auxiliary winding or output-derived biasing above 9.5 V. Protection includes hysteretic thermal shutdown (150 °C trip, 30 °C hysteresis), burst mode operation below VCOMP = 1.1 V, and OLP with 50 ms overload timer and full automatic restart.

Key Specifications

Pinout & Package

VIPER26HN is available in two thermally optimized packages: DIP-7 (1 W max power dissipation @ Tamb < 40 °C) and SO16N narrow (1.5 W @ Tamb < 60 °C). Both require copper pour under DRAIN pins (pins 1–2 in DIP-7; pins 13–16 in SO16N) for effective junction-to-ambient thermal resistance reduction.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ICE2QS03G and LNK306P, VIPER26HN provides superior EMI performance via ±8 kHz jitter, lower no-load consumption (<30 mW), and flexible current limit configuration-making it optimal for cost-sensitive, high-reliability auxiliary supplies demanding regulatory compliance and thermal robustness.

Availability

VIPER26HN is available at Aetrix Electronics and suitable for auxiliary power supply for appliances, LED drivers, and SMPS for set-top boxes requiring stable component supply, long-term lifecycle assurance, and consistent parametric performance across production batches.

Supply support for VIPER26HN 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 analog devices for industrial, automotive, and consumer markets.

VIPER26HN belongs to the VIPer plus family of high-voltage offline controllers engineered specifically for compact, low-component-count AC-DC converters targeting energy-efficient auxiliary and low-power main supplies in white goods and smart home devices.

FAQ

What is the maximum continuous output power achievable with VIPER26HN in an open-frame design?

VIPER26HN delivers up to 12 W continuous output power in open-frame flyback configurations at 50 °C ambient temperature with adequate PCB copper pour under DRAIN pins. This rating assumes SO16N package mounted on FR4 with 100 mm² of 35 µm copper, per DS6901 Rev 3 Table 8. Power derates linearly above 50 °C due to thermal limits.

How does the LIM pin adjust the drain current limit, and what is the minimum achievable IDLIM?

The LIM pin sinks current proportional to an external resistor (RLIM) connected to GND; decreasing RLIM lowers IDLIM from its default 0.7 A. Per Figure 12 in DS6901, a 10 kΩ RLIM reduces IDLIM to ~0.35 A at 25 °C. Values below 1 kΩ are not recommended due to excessive current draw and potential noise sensitivity.

Can VIPER26HN operate in isolated flyback topologies without an optocoupler?

No-VIPER26HN requires optocoupler feedback in isolated flyback designs. The FB pin must be shorted to GND to disable the internal error amplifier, and the COMP pin driven directly by the optocoupler's phototransistor to close the regulation loop. Direct primary-side sensing is unsupported; isolation accuracy depends on optocoupler CTR and compensation network design.

What thermal design considerations apply to the DRAIN pins in DIP-7 versus SO16N packages?

Both packages require dedicated copper pour under DRAIN pins for thermal conduction: DIP-7 uses pins 1–2; SO16N uses pins 13–16. For SO16N, 100 mm² of 35 µm copper reduces RTH-JA from 120 °C/W to 85 °C/W; DIP-7 achieves 95 °C/W under same conditions. Thermal vias to inner layers are recommended but not sufficient alone-copper area must dominate heat spreading.