STMicroelectronics VIPER15LN

Overview

VIPER15LN from STMicroelectronics is an off-line high-voltage PWM controller IC with integrated 800 V avalanche-rugged N-channel MOSFET, quasi-resonant (QR) valley-switching control, adjustable current limiting via ZCD pin, hysteretic thermal shutdown at 150 °C, and <50 mW standby power at 265 Vac. It targets low-cost flyback SMPS in consumer adapters and auxiliary supplies.

For engineers reviewing the VIPER15LN datasheet, VIPER15LN pinout, VIPER15LN application, or VIPER15LN equivalent, key selection considerations include its DIP-7 package, 20 Ω R_DS(on) at 25 °C, 0.4 A primary-side current limit, 13–15 V V_DDon startup threshold, and built-in brown-out protection with 0.45 V threshold and 50 mV hysteresis.

Technical Context

The VIPER15LN integrates a high-voltage start-up generator drawing current directly from the DRAIN pin (60–100 V turn-on), enabling self-biasing without external HV resistor networks. Its ZCD pin serves three concurrent functions: zero-current detection for QR operation, user-defined current limit set-point via RLIM resistor, and overvoltage protection strobing with 2.2 µs digital filtering.

Control logic includes frequency foldback, valley skipping, burst-mode operation below 0.5 V FB input, and dual-level overcurrent protection-first level at 0.4 A (adjustable), second level at 0.6 A triggering hiccup-mode auto-restart. Thermal shutdown activates at 150–160 °C with 30 °C hysteresis, and brown-out protection disables switching when BR pin voltage falls below 0.45 V.

Key Specifications

Pinout & Package

VIPER15LN is housed in a 7-pin dual-in-line plastic package (DIP-7) with pins 7 and 8 internally connected to the metal drain frame for enhanced thermal dissipation. The copper pad under pins 7–8 must be designed as a heatsink area on PCB.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ICE2QS03G and LNK306P, VIPER15LN delivers lower system cost through integrated HV start-up, unified ZCD functionality, and guaranteed <50 mW standby-reducing component count and layout complexity in compact DIP-7 designs.

Availability

VIPER15LN is available at Aetrix Electronics and suitable for AC/DC adapters, auxiliary power supplies, and no-electrolytic LED drivers requiring stable component supply across industrial and consumer production programs.

Supply support for VIPER15LN 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, specializing in power management, microcontrollers, and analog/mixed-signal ICs for industrial, automotive, and consumer markets.

VIPER15LN belongs to ST's VIPer™ family of off-line high-voltage converters, engineered specifically for cost-optimized, low-component-count flyback SMPS targeting energy-efficient consumer and industrial auxiliary power applications.

FAQ

What is the maximum continuous output power achievable with VIPER15LN in a DIP-7 open-frame design?

VIPER15LN supports up to 6 W continuous output power in open-frame configurations at 50 °C ambient with adequate heatsinking on pins 7–8, as specified in Table 2 of the datasheet. This assumes proper PCB copper area (≥100 mm²) under the drain pins and optimized transformer design for QR operation.

How does the ZCD pin enable both current limiting and overvoltage protection?

The ZCD pin performs three functions: (1) it senses transformer demagnetization for QR timing; (2) its voltage drop across RLIM resistor sets the primary current limit; (3) if voltage exceeds 4.2 V, it triggers digitally filtered OVP shutdown. These share the same pin but operate on distinct internal comparators and timing paths.

Can VIPER15LN operate without an auxiliary winding for VDD supply?

No-VIPER15LN requires an auxiliary winding to sustain VDD after startup. The internal HV start-up circuit only charges the VDD capacitor initially; once VDD reaches 15 V, the HV generator disables and the IC relies entirely on auxiliary-derived supply for continuous operation.

What is the purpose of the BR pin, and how should it be configured if unused?

The BR pin provides brown-out protection by disabling switching when input voltage sags below 0.45 V. If unused, it must be connected directly to GND to prevent floating input, which could cause erratic shutdown behavior due to noise sensitivity on this high-impedance node.