STMicroelectronics VIPER114HSTR

Overview

VIPER114HSTR from STMicroelectronics is a high-voltage offline PWM controller IC integrating an 800 V avalanche-rugged N-channel MOSFET, current-mode control, and embedded HV startup. It delivers 12 W in open-frame designs at 50 °C ambient, supports flyback/buck/buck-boost topologies, and operates with 120 kHz ±7% jittered switching frequency for EMI reduction. Used in low-power SMPS for home appliances and industrial controls.

For engineers reviewing the VIPER114HSTR datasheet, VIPER114HSTR pinout, VIPER114HSTR application, or VIPER114HSTR equivalent, key selection criteria include drain current limit (480 mA), VCC operating range (4.5–30 V), no-load input power (<10 mW at 230 VAC), thermal shutdown (150 °C), and SSOP10 package compatibility with PCB copper-area heatsinking.

Technical Context

The VIPER114HSTR implements current-mode PWM control with an integrated 800 V MOSFET and sense-FET for lossless primary-side current sensing. Its oscillator provides fixed 120 kHz ±7% jittered frequency to spread spectral energy and reduce conducted EMI filter size.

It features pulse-skipping protection to prevent flux-runaway during startup, auto-restart after OLP/OVP faults, and direct feedback via a transconductance error amplifier referenced to 1.2 V. The HV startup circuit delivers up to 8.5 mA charging current to VCC at startup, enabling self-supply operation after initial turn-on.

Key Specifications

Pinout & Package

Package: SSOP10 (Shrink Small Outline Package, 10-pin, 3.9 mm × 4.9 mm, 0.65 mm pitch), with pins 6–10 internally bonded to MOSFET drain metal pad for enhanced thermal conduction to PCB copper area.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ICE2QS03G and LNK364PG, VIPER114HSTR offers superior universal-input robustness (800 V), lower no-load consumption, jittered frequency for smaller filters, and integrated DIS/FB/COMP functionality-making it optimal for space-constrained, high-efficiency industrial and appliance SMPS where reliability and regulatory compliance are critical.

Availability

VIPER114HSTR is available at Aetrix Electronics and suitable for home appliance power supplies, industrial sensor node PSUs, smart lighting drivers, and low-power IoT adapters requiring stable component supply across extended product lifecycles.

Supply support for VIPER114HSTR 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 solutions for industrial, automotive, and consumer markets.

VIPER11 is ST's dedicated energy-saving offline high-voltage converter family, engineered to replace discrete MOSFET+controller designs in sub-12 W AC-DC applications while meeting global efficiency standards like DOE Level VI and EU CoC Tier 2.

FAQ

What is the maximum continuous output power achievable with VIPER114HSTR in an open-frame design?

VIPER114HSTR delivers up to 12 W continuous output power in open-frame configurations at 50 °C ambient temperature with adequate PCB copper heatsinking. This rating assumes proper layout-especially thermal copper area under pins 6–10-and operation within the 120 kHz switching frequency variant. Derating is required above 50 °C or in enclosed, non-ventilated enclosures.

How does the jittered oscillator improve EMI performance compared to fixed-frequency alternatives?

The 120 kHz ±7% jittered oscillator spreads switching energy across a 16.8 kHz bandwidth (±7% of 120 kHz) at 260 Hz modulation rate. This reduces peak harmonic amplitudes by ~10 dB versus fixed-frequency operation, allowing smaller input EMI filters-typically cutting common-mode choke size by 30–40% and X-capacitor value by 25% while maintaining CISPR 22 Class B compliance.

Can VIPER114HSTR operate with secondary-side optocoupler feedback, and how is COMP pin used in that configuration?

Yes-VIPER114HSTR supports secondary-side regulation via optocoupler feedback. In this mode, the internal error amplifier is disabled by grounding the FB pin, and the COMP pin becomes a high-impedance current sink driven directly by the optocoupler's phototransistor collector. A pull-up resistor to VCC sets the current limit setpoint, enabling precise output voltage regulation independent of transformer turns ratio or primary-side component tolerances.

What thermal design considerations are critical for reliable operation at full load?

Reliable full-load operation requires minimizing junction-to-ambient thermal resistance: mount VIPER114HSTR on a minimum 100 mm² copper area (35 μm thick) under pins 6–10, use thermal vias to inner/ground planes, and avoid routing high-current traces near GND pin 1. With this layout, R_TH-JA drops to 95 °C/W, limiting junction rise to ~90 °C at 12 W dissipation-well below the 150 °C thermal shutdown threshold.