STMicroelectronics VIPER115LSTR

Overview

VIPER115LSTR from STMicroelectronics is a high-voltage offline PWM converter IC integrating an 800 V avalanche-rugged N-channel MOSFET, current-mode PWM controller, embedded HV startup circuit, and sense-FET. It delivers up to 12 W in open-frame designs at 50 °C ambient, supports flyback/buck/buck-boost topologies, and operates with 60 kHz ±7% jittered switching frequency for EMI reduction. Used in low-power SMPS for home appliances and industrial controls.

For engineers reviewing the VIPER115LSTR datasheet, VIPER115LSTR pinout, VIPER115LSTR application, or VIPER115LSTR 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 (150 °C), and SSOP10 package compatibility with PCB copper-area heatsinking.

Technical Context

The VIPER115LSTR implements a current-mode PWM architecture with integrated 800 V power MOSFET and dedicated sense-FET for lossless primary-side current sensing. Its oscillator provides fixed 60 kHz nominal frequency with ±7% spread-spectrum jitter at 260 Hz to suppress conducted EMI peaks.

Control logic includes pulse-skipping protection to prevent flux-runaway during startup, auto-restart OLP/short-circuit protection, and direct feedback via transconductance error amplifier (1.2 V reference) with COMP output driving peak-current setpoint. Soft-start ramps current limit over 8 ms to limit inrush stress.

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 offline high-voltage converter applications.

Compared with ICE2QS03G and LNK364PG, VIPER115LSTR offers superior EMI performance via jitter, lower no-load consumption, and flexible disable functionality-making it optimal for compact, energy-certified designs where thermal and EMC margins are tight.

Availability

VIPER115LSTR is available at Aetrix Electronics and suitable for home appliance SMPS, industrial sensor power supplies, and IoT gateway adapters requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for VIPER115LSTR 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, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

VIPER11 is ST's energy-efficient offline converter product line targeting low-power (<15 W) AC-DC applications, emphasizing integration, ultra-low standby power, and robust protection for cost-sensitive, space-constrained designs.

FAQ

What is the maximum continuous output power achievable with VIPER115LSTR in an open-frame design?

The VIPER115LSTR delivers up to 12 W of continuous output power in open-frame configurations at 50 °C ambient temperature, as confirmed in ST's DS11873 Rev 5 datasheet Table 8. This assumes adequate PCB copper heatsinking (100 mm² Cu pour under DRAIN pins) and proper layout per Section 6.3. Power derates linearly above 50 °C due to thermal shutdown activation at 150 °C junction temperature.

Can VIPER115LSTR operate without an auxiliary winding in isolated flyback designs?

No-VIPER115LSTR requires an auxiliary winding for steady-state operation in isolated topologies. The internal HV startup current source only charges VCC during initial power-up; once running, the IC must be powered from the auxiliary winding. Direct VCC connection to rectified mains is unsafe and violates absolute maximum ratings (VCC max = 30 V).

How does the DIS pin enable output overvoltage protection in non-isolated buck converters?

In non-isolated buck topologies, a resistive divider from the regulated output to the DIS pin triggers shutdown when output exceeds ~2× the divider ratio × 1.2 V threshold. For example, a 10:1 divider trips DIS at 12 V output. After 500 ms auto-restart delay, normal operation resumes if the fault clears-providing self-recovering OVP without external supervisor IC.

Is the SSOP10 package of VIPER115LSTR RoHS-compliant and halogen-free?

Yes-VIPER115LSTR is manufactured in ST's RoHS-compliant, halogen-free SSOP10 package, as documented in ST's official packaging information (Section 7.1, DS11873 Rev 5). The device carries the "E" suffix per ST's ordering nomenclature, indicating lead-free and halogen-free construction per JEDEC JS709B and IEC 61249-2-21 standards.