STMicroelectronics VIPER115XSTR

Overview

VIPER115XSTR from STMicroelectronics is a high-voltage offline PWM converter IC integrating an 800 V avalanche-rugged N-channel MOSFET, current-mode controller, HV startup circuitry, and embedded error amplifier. It delivers up to 12 W in open-frame designs at 50 °C ambient, supports flyback/buck/buck-boost topologies, and operates with 30 kHz ±7% jittered switching frequency for EMI reduction. Used in low-power SMPS for home appliances and industrial controls.

For engineers reviewing the VIPER115XSTR datasheet, VIPER115XSTR pinout, VIPER115XSTR application, or VIPER115XSTR equivalent, key selection criteria include drain current limit (590 mA), VCC operating range (4.5–30 V), no-load input power (<10 mW at 230 VAC), thermal shutdown threshold (150 °C), and SSOP10 package compatibility with PCB copper-area heatsinking.

Technical Context

The VIPER115XSTR implements a current-mode PWM control architecture with integrated 800 V power MOSFET and sense-FET, enabling direct primary-side regulation without optocoupler in non-isolated topologies. Its jittered oscillator (30 kHz ±7%) spreads spectral energy to reduce conducted EMI, while pulse-skipping prevents flux runaway during startup by dynamically skipping cycles when peak drain current exceeds 590 mA within minimum on-time (300 ns).

It features dual-stage HV startup: initial linear charging of VCC via ICH1 (1 mA typ.) at low VCC, ramping to ICH2 (3 mA typ.) above 1 V, then disabling upon reaching VCCon (16 V typ.). Protection includes auto-restart OLP, line/output OVP, max duty-cycle counter, VCC clamp (32.5 V typ.), and thermal shutdown (150 °C typ.).

Key Specifications

Pinout & Package

Package: SSOP10 (3.9 mm × 4.9 mm, 0.65 mm pitch), thermally enhanced with DRAIN pins (6–10) connected to internal MOSFET metal pad for direct PCB copper-area heatsinking (R_TH-JA = 95 °C/W with 100 mm² Cu).

Key Features

Applications

Equivalent & Alternatives

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

Compared with ICE2QS03G and LNK364PG, VIPER115XSTR uniquely combines 800 V ruggedness, jittered 30 kHz operation, direct FB capability, and sub-10 mW no-load consumption-enabling simpler, smaller, and more energy-compliant SMPS in space-constrained white goods and smart lighting.

Availability

VIPER115XSTR is available at Aetrix Electronics and suitable for smart home lighting drivers, industrial sensor power supplies, white goods auxiliary PSUs, and low-power IoT gateway adapters requiring stable component supply across automotive-grade temperature ranges and long-lifecycle production programs.

Supply support for VIPER115XSTR 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, and analog/mixed-signal devices for industrial, automotive, and consumer markets.

The VIPer™ product line targets highly integrated, energy-efficient offline AC-DC conversion-specifically engineered to replace discrete MOSFET + controller solutions in sub-25 W applications with minimal external components and certified energy compliance.

FAQ

What is the maximum continuous output power achievable with VIPER115XSTR in an open-frame design?

VIPER115XSTR delivers up to 12 W continuous output power in open-frame configurations at 50 °C ambient temperature with adequate PCB copper-area heatsinking (100 mm²). This rating assumes 230 VAC input, 30 kHz operation, and proper thermal layout per ST's AN4175 guidelines-exceeding 12 W risks thermal shutdown due to its 150 °C junction limit and 95 °C/W R_TH-JA.

Can VIPER115XSTR operate without an auxiliary winding in a flyback converter?

Yes-VIPER115XSTR supports self-supply from the output in non-isolated topologies or from an auxiliary winding in isolated designs. Its integrated HV startup current source (ICH2 = 3 mA typ.) charges VCC directly from DRAIN during startup, eliminating need for auxiliary winding in buck or buck-boost configurations. For isolated flyback, auxiliary winding is recommended for stable steady-state operation.

How does the DIS pin function for overvoltage protection?

The DIS pin triggers automatic 500 ms disable-and-restart cycle when voltage exceeds 1.2 V for >1 ms. For output OVP in non-isolated converters, a resistor divider from output to DIS sets trip point (e.g., 12 V output → 100 kΩ/12 kΩ yields ~1.2 V at DIS). In isolated designs, it can monitor rectified mains via another divider for line OVP-bypassing optocoupler dependency.

What layout practices are critical for thermal performance in SSOP10?

Thermal performance depends critically on connecting pins 6–10 (DRAIN) to ≥100 mm² of 35 µm-thick copper on the PCB bottom layer, with ≥4 thermal vias (0.3 mm diameter) per pin to inner/ground planes. GND pin (1) must have separate low-impedance trace to this copper area-never shared with high-di/dt return paths-to avoid noise injection into the control loop and ensure R_TH-JA ≤95 °C/W.