STMicroelectronics VIPER06LSTR

Overview

VIPER06LSTR from STMicroelectronics is a high-voltage offline flyback controller IC with integrated 800 V avalanche-rugged power MOSFET, fixed 60 kHz switching frequency, <30 mW standby power at 265 VAC, and adjustable current limiting via the LIM pin. It enables self-biased, auxiliary-winding-free power supplies for low-power AC/DC conversion in home appliance control boards and LED drivers.

For engineers reviewing the VIPER06LSTR datasheet, VIPER06LSTR pinout, VIPER06LSTR application, or VIPER06LSTR equivalent, key selection criteria include its 800 V drain rating, internal soft-start, burst-mode operation for energy compliance, thermal shutdown hysteresis, and direct mains-powered startup without auxiliary winding.

Technical Context

The VIPER06LSTR integrates a current-mode PWM controller with a SenseFET-based drain current sensing path and an internal transconductance error amplifier referenced to 3.3 V on the FB pin. Its oscillator delivers fixed 60 kHz switching with ±4 kHz jitter at 230 Hz to reduce EMI peak emissions.

Startup is managed by a high-voltage current generator sourcing −1.8 mA from DRAIN pins until VDD reaches 12–14 V; thereafter, operation transitions to VDD capacitor supply. Fault handling includes hysteretic thermal shutdown (150–160 °C), safe auto-restart after overload (1 s restart delay), and open-loop failure detection via VDD clamp monitoring.

Key Specifications

Pinout & Package

The VIPER06LSTR is housed in a surface-mount SSO10 package with exposed metal pad for thermal dissipation; DRAIN pins (6–10) are internally bonded to the metal frame and must be connected to large copper areas on PCB for effective heat transfer.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar offline flyback controller applications.

Compared with ICE2QS03G and LNK306P, the VIPER06LSTR offers the lowest system-level component count due to its integrated 800 V MOSFET and self-biasing startup, while providing unique LIM-pin current limit adjustability - critical for optimizing transformer utilization and fault margin in cost-sensitive industrial controls.

Availability

VIPER06LSTR is available at Aetrix Electronics and suitable for smart home power supplies, LED lighting drivers, electric meter auxiliary supplies, and appliance control board power requiring stable component supply across extended product lifecycles.

Supply support for VIPER06LSTR 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.

The VIPER series targets cost-sensitive, low-to-mid power AC/DC conversion, emphasizing integration, energy efficiency, and robustness in mains-connected applications without auxiliary windings.

FAQ

What is the maximum continuous output power achievable with VIPER06LSTR in an open-frame design?

At 50 °C ambient with adequate heatsinking, the VIPER06LSTR delivers up to 5 W continuously in open-frame configurations. This is limited by thermal resistance (R_thJA = 90 °C/W on standard FR4) and internal power dissipation constraints - exceeding this requires forced air or enhanced copper pour to maintain junction temperature below 150 °C.

Can VIPER06LSTR operate in isolated flyback topologies without an optocoupler?

Yes - it supports optocoupler-less isolated flyback using primary-side regulation (PSR) techniques. The FB pin is shorted to GND to disable the internal error amplifier, and regulation is achieved by sampling reflected auxiliary winding voltage during MOSFET off-time, leveraging the COMP pin's dynamic range and burst-mode behavior for stability.

How does the LIM pin adjustment affect short-circuit protection response time?

Reducing the current limit via the LIM pin lowers the peak drain current threshold but does not change the overload timer (t_OVL = 50 ms) or restart delay (t_RESTART = 1 s). However, a lower ID_lim causes earlier current-limit activation during faults, reducing energy per cycle and lowering thermal stress on the internal MOSFET during sustained short-circuit events.

Is the 800 V drain rating valid for repetitive avalanche conditions?

Yes - the datasheet specifies 2 mJ repetitive avalanche energy (E_AV) and 1 A repetitive avalanche current (I_AR) at T_J = 150 °C. This rating enables reliable operation during line surges and transformer leakage inductance spikes without external snubbers, provided layout minimizes parasitic inductance in the DRAIN loop.