STMicroelectronics VIPER012XSTR

Overview

VIPER012XSTR from STMicroelectronics is a high-voltage off-line SMPS controller integrating an 800 V avalanche-rugged N-channel power MOSFET, current-mode PWM control, and embedded HV startup circuitry. It delivers up to 4 W in open-frame designs at 230 VAC input, supports flyback/buck/buck-boost topologies, and operates with 30 kHz ±7% jittered switching frequency for EMI reduction.

For engineers reviewing the VIPER012XSTR datasheet, VIPER012XSTR pinout, VIPER012XSTR application, or VIPER012XSTR equivalent, key selection criteria include its self-supply capability (eliminating auxiliary winding), <10 mW no-load consumption at 230 VAC, integrated thermal shutdown, drain current limit of 240 mA (typ.), and SSOP10 package with five DRAIN pins for enhanced thermal dissipation.

Technical Context

The device implements a fixed-frequency current-mode PWM controller with jittered oscillator (±7% spread at 260 Hz) to reduce peak EMI emissions. Its internal transconductance error amplifier features a 1.2 V reference and supports both primary-side regulation (via FB voltage divider to VCC) and secondary-side feedback (via optocoupler driving COMP).

Startup is managed by an embedded 800 V HV start-up FET and switchable current source (ICH1–ICH3), enabling self-supply operation where VCC is recharged only during MOSFET OFF time. Protection logic includes pulse-skip to prevent flux-runaway, automatic-restart OLP/OLP delay (100 ms typ. for X-type), and thermal shutdown at 155 °C (typ.).

Key Specifications

Pinout & Package

Package: SSOP10 (3.9 mm × 4.9 mm, 0.65 mm pitch), thermally enhanced with exposed metal pad connected to DRAIN pins (6–10) for direct PCB copper area heat sinking.

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 LNK3206P, VIPER012XSTR offers superior energy efficiency (<10 mW no-load), built-in jitter for EMI reduction, and true self-supply operation-enabling simpler, smaller, and more globally compliant low-power SMPS designs.

Availability

VIPER012XSTR is available at Aetrix Electronics and suitable for home appliance power supplies, smart lighting drivers, and industrial sensor node PSUs requiring stable component supply across global manufacturing sites.

Supply support for VIPER012XSTR 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.

VIPER01 series belongs to ST's Energy Saving Off-line High Voltage Converter product line, engineered specifically for ultra-low standby power, universal AC input compatibility, and minimal external component count in sub-10 W SMPS applications.

FAQ

What is the maximum continuous output power achievable with VIPER012XSTR in an open-frame design?

VIPER012XSTR delivers up to 4.5 W continuous output power in open-frame configurations at 50 °C ambient temperature with adequate PCB copper heatsinking (100 mm² Cu). This rating assumes 230 VAC input, proper thermal layout per DS11423, and use of recommended external components (e.g., 30 Ω startup resistor, 10 µF VCC capacitor). Derating applies above 50 °C ambient or with reduced copper area.

Can VIPER012XSTR operate without an auxiliary winding or external bias supply?

Yes. VIPER012XSTR supports self-supply mode: its internal HV current source recharges the VCC capacitor during MOSFET OFF time, eliminating the need for an auxiliary winding or external bias supply. In this mode, VCC decays to ~4.25 V before the HV source reactivates, sustaining operation with only one capacitor (CS) connected between VCC and GND.

How does the DIS pin function for overvoltage protection?

The DIS pin triggers auto-restart protection when voltage exceeds 1.2 V for >1 ms. For line OVP, connect a resistive divider from rectified mains to DIS; for output OVP in non-isolated topologies, connect a divider from output to DIS. If unused, solder DIS directly to GND to disable the function-no pull-down resistor required.

What thermal resistance values apply to VIPER012XSTR in standard PCB layouts?

When mounted on a standard single-sided FR4 board with 100 mm² of 35 µm-thick copper, VIPER012XSTR achieves R_TH-JA = 95 °C/W and R_TH-JC = 5 °C/W. With minimal copper (standard layout), R_TH-JA rises to 155 °C/W. The five DRAIN pins are internally connected to the MOSFET die pad, so maximizing copper area under pins 6–10 is critical for thermal performance.