STMicroelectronics VIPER26LD

Overview

VIPER26LD 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 oscillator (60 kHz ±4 kHz). It delivers up to 12 W in open-frame designs at 50 °C ambient, supports flyback/buck/buck-boost topologies, and achieves <30 mW no-load input power at 230 VAC - enabling auxiliary power supplies for appliances and LED drivers.

For engineers reviewing the VIPER26LD datasheet, VIPER26LD pinout, VIPER26LD application, or VIPER26LD equivalent, key selection criteria include its DIP-7/SO16N dual-package support, adjustable current limit via LIM pin, burst-mode operation with 1.1 V COMP threshold, thermal shutdown at 150 °C, and integrated error amplifier with 3.3 V FB reference.

Technical Context

The VIPER26LD implements a fixed-frequency current-mode PWM control architecture with internal SenseFET-based current sensing, cycle-by-cycle OCP, and programmable soft-start (8.5 ms). Its HV startup current source activates at 90 V DRAIN voltage and delivers −1.8 mA to charge VDD during startup before switching transitions to auxiliary winding supply.

It features a jittered oscillator (±4 kHz spread at 230 Hz modulation) to reduce EMI filter cost, burst-mode entry at VCOMP ≤ 1.1 V with hysteresis of 40 mV, and thermal protection with 30 °C hysteresis. The integrated error amplifier has 2 mA/V transconductance and is disabled in isolated configurations by shorting FB to GND.

Key Specifications

Pinout & Package

VIPER26LD is available in DIP-7 and SO16 narrow packages. Both variants share identical pin functions but differ in terminal count and layout. Thermal design requires copper pour under DRAIN pins (pins 1–2 in DIP-7; pins 13–16 in SO16N) to achieve R_TH-JA ≤ 95 °C/W.

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, VIPER26LD offers superior energy efficiency via burst mode and integrated HV startup, wider input voltage coverage due to 800 V rating, and precise current limit tuning - making it optimal for globally certified, thermally constrained auxiliary supplies.

Availability

VIPER26LD is available at Aetrix Electronics and suitable for appliance auxiliary supplies, smart metering systems, and LED driver reference designs requiring stable component supply across industrial temperature ranges and long product lifecycles.

Supply support for VIPER26LD 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, MCU, power, and sensor solutions for automotive, industrial, and consumer markets.

VIPER26LD belongs to the VIPerPlus family of high-voltage offline controllers engineered specifically for compact, low-noise, energy-compliant AC-DC conversion in sub-20 W applications - emphasizing integration, thermal robustness, and regulatory readiness.

FAQ

What package options does VIPER26LD support?

VIPER26LD is offered in both DIP-7 and SO16 narrow packages. DIP-7 uses pins 1–8 with GND on pins 1–2 and DRAIN on pins 1–2; SO16N uses pins 1–16 with GND on pins 1–2, DRAIN on pins 13–16, and N.C. on pins 9–12. Thermal pad design differs significantly between packages - SO16N requires 100 mm² copper pour for R_TH-JA = 85 °C/W.

How is current limit adjusted on VIPER26LD?

Current limit is adjusted by connecting an external resistor between the LIM pin and GND. A 100 kΩ resistor sets IDLIM ≈ 0.35 A; 10 kΩ yields ≈ 0.6 A. Leaving LIM open retains the default 0.7 A limit. Capacitors on LIM must stay below 470 nF to avoid loop instability, per DS6901 Section 9.

Does VIPER26LD support primary-side regulation without optocouplers?

Yes - VIPER26LD supports primary-side regulation in flyback topologies by connecting the FB pin to the VCC rail through a resistor divider. This eliminates optocouplers and TL431, relying on reflected voltage sampling. The internal error amplifier remains active, and COMP drives the PWM comparator directly.

What protections are built into VIPER26LD?

VIPER26LD integrates overload/short-circuit protection with automatic restart, feedback loop disconnection detection, hysteretic thermal shutdown (150 °C), and undervoltage lockout (VDDoff = 8 V). All protections trigger automatic recovery after fault removal - no external latch or reset circuitry required.