STMicroelectronics VIPER16HN

Overview

VIPER16HN from STMicroelectronics is a fixed-frequency off-line PWM controller with integrated 800 V avalanche-rugged power MOSFET, designed for low-power AC-DC flyback and buck-boost converters. It delivers up to 10 W in open-frame designs at 50 °C ambient, operates at 115 kHz (±8 kHz jitter), supports self-biasing without auxiliary winding, and achieves <30 mW standby power at 230 VAC - enabling compliance with global energy-saving regulations in auxiliary power supplies for appliances and smart meters.

For engineers reviewing the VIPER16HN datasheet, VIPER16HN pinout, VIPER16HN application, or VIPER16HN equivalent, this device is selected for high-voltage primary-side regulation where integrated HV start-up, adjustable overcurrent limit, burst-mode operation, and hysteretic thermal shutdown are critical for robust, low-BOM-count offline SMPS designs.

Technical Context

The VIPER16HN implements a current-mode PWM controller with cycle-by-cycle drain current sensing via an internal SenseFET, enabling precise peak-current limiting and stable loop control. Its oscillator provides fixed 115 kHz switching with ±8 kHz frequency jitter at 230 Hz to reduce EMI peak amplitudes without external spread-spectrum circuitry.

It integrates a high-voltage current generator sourcing −7 to −14 mA from the DRAIN pin during MOSFET off-time for self-supply, eliminating need for auxiliary winding. Protection features include open-loop failure detection, safe auto-restart after overload (t_OVL = 50 ms, t_RESTART = 1 s), and hysteretic thermal shutdown (T_SD = 150–160 °C, THYST = 30 °C).

Key Specifications

Pinout & Package

VIPER16HN is housed in SO16 narrow (SOIC-16) package with exposed DRAIN pins (pins 13–16) thermally connected to the metal frame for enhanced heat dissipation. The copper area under DRAIN pins must be maximized per layout guidelines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ICE2QS03G and LNK306P, VIPER16HN uniquely combines 800 V ruggedness, jittered 115 kHz operation, programmable current limit, and true auxiliary-winding-free self-biasing - making it optimal for compact, low-noise, high-efficiency <10 W auxiliary supplies where thermal and EMI margins are tight.

Availability

VIPER16HN is available at Aetrix Electronics and suitable for smart metering, appliance control boards, industrial sensor nodes, and LED driver auxiliary supplies requiring stable component supply across long-lifecycle industrial programs.

Supply support for VIPER16HN 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, specializing in power management, microcontrollers, and analog ICs for industrial, automotive, and consumer markets.

VIPER16HN belongs to the VIPer™ plus family - a line of highly integrated off-line controllers designed specifically for cost-sensitive, space-constrained AC-DC power conversion in sub-15 W applications.

FAQ

What is the maximum continuous output power of VIPER16HN in an open-frame design?

VIPER16HN delivers up to 10 W continuous output power in open-frame configurations at 50 °C ambient temperature with adequate heatsinking, as confirmed in Table 2 of the official datasheet (DocID15232 Rev 7). This rating assumes proper PCB copper area under DRAIN pins and standard FR4 layout per Section 16 guidelines.

Can VIPER16HN operate without an auxiliary winding?

Yes - VIPER16HN incorporates an integrated high-voltage current generator that draws bias current directly from the DRAIN pin, enabling self-supply without auxiliary winding. This is validated in Section 8 of the datasheet and demonstrated in Figure 17–20 typical circuits for flyback and buck-boost topologies.

How is the overcurrent limit adjusted using the LIM pin?

The LIM pin sinks current proportional to an external resistor (R_LIM) connected between LIM and GND. As R_LIM decreases, the peak drain current limit (I_Dlim) reduces linearly from its default 0.4 A value. Figure 13 and Section 11 specify the relationship: I_Dlim ≈ 0.4 A × (1 − R_LIM/82 kΩ) for R_LIM ≤ 80 kΩ.

Does VIPER16HN support both isolated and non-isolated topologies?

Yes - VIPER16HN supports both configurations. In non-isolated topologies (e.g., buck-boost), FB is used directly as the error amplifier input. In isolated flyback designs, FB is shorted to GND to disable the internal amplifier, and feedback is closed via optocoupler into the COMP pin, as shown in Figure 22 and described in Section 12 of the datasheet.