STMicroelectronics VIPER16LD

Overview

VIPER16LD 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 60 kHz with ±4 kHz frequency jittering, supports self-biasing without auxiliary winding, and achieves <30 mW standby power at 230 VAC - enabling compliance with stringent energy-saving regulations in auxiliary power supplies for appliances and smart meters.

For engineers reviewing the VIPER16LD datasheet, VIPER16LD pinout, VIPER16LD application, or VIPER16LD equivalent, this device is selected for cost-sensitive, compact, no-aux-winding offline SMPS where EMI reduction via spread-spectrum jittering, adjustable overcurrent limit, and safe auto-restart after short-circuit are critical design requirements.

Technical Context

The VIPER16LD integrates a high-voltage current generator referenced to the DRAIN pin, enabling direct startup from rectified mains and self-supply during operation without an auxiliary winding. Its current-mode PWM controller uses cycle-by-cycle drain current sensing via SenseFET architecture and compares against either a fixed IDlim = 0.4 A (typ) or user-adjusted threshold via external resistor on LIM pin.

It implements burst mode operation below VCOMPL = 1.1 V (typ), reducing average switching frequency to hundreds of Hz and cutting quiescent supply current to 0.6 mA (non-switching). Thermal protection features hysteretic shutdown at TJ = 155 °C (typ) with 30 °C hysteresis, and fault recovery includes soft-start–enabled auto-restart after tRESTART = 1 s following overload or short-circuit events.

Key Specifications

Pinout & Package

VIPER16LD is supplied in SO16 narrow (SOIC-16) package with exposed thermal pad connected to DRAIN pins (13–16) for enhanced heat dissipation. The package supports surface-mount assembly and meets industrial thermal requirements when mounted on FR4 with ≥100 mm² copper pour.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar off-line PWM controller applications.

Compared with ICE2QS03G and LNK304P, VIPER16LD uniquely combines 800 V ruggedness, no-aux-winding operation, adjustable current limit, and jittered 60 kHz switching - making it optimal for space-constrained, ultra-low-standby, and surge-prone auxiliary supplies where design flexibility and EMI headroom are critical.

Availability

VIPER16LD is available at Aetrix Electronics and suitable for smart metering, appliance auxiliary power, and industrial sensor node power supplies requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for VIPER16LD 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, delivering innovative solutions across automotive, industrial, power, and microcontroller markets.

VIPER16LD belongs to the VIPer™ plus family of high-voltage off-line controllers, engineered specifically for cost-effective, compact, and energy-efficient AC-DC conversion in sub-15 W applications without auxiliary windings.

FAQ

What is the maximum continuous output power achievable with VIPER16LD in an open-frame design?

VIPER16LD delivers up to 10 W continuous output power in open-frame configurations at 50 °C ambient temperature with adequate heatsinking, as verified in ST's typical power characterization (Table 2, DocID15232 Rev 7). This assumes proper PCB layout with ≥100 mm² copper pour under DRAIN pins and operation at 230 VAC input.

Can VIPER16LD operate without an auxiliary winding, and how is bias supplied?

Yes - VIPER16LD eliminates the need for an auxiliary winding via its integrated high-voltage current generator, which sources startup and operating current directly from the DRAIN pin. During startup, it delivers −1.8 mA (typ) to charge the VDD capacitor until VDD reaches 13 V; in steady state, it replenishes VDD during MOSFET off-time.

How does the LIM pin adjust the current limit, and what is the minimum achievable value?

The LIM pin sinks current proportional to an external resistor (RLIM) connected to GND. With RLIM = 47 kΩ, IDlim reduces to ~0.2 A; at RLIM = 82 kΩ, it drops to ~0.1 A (per Figure 13). Values below 0.1 A are not supported - the internal OCP comparator retains minimum functional threshold.

Does VIPER16LD support both isolated and non-isolated topologies, and how is feedback configured?

Yes - for non-isolated topologies (e.g., buck-boost), FB is connected directly to output via single resistor (VOUT = 3.3 V) or divider; for isolated flyback, FB is shorted to GND to disable internal error amplifier, and COMP drives optocoupler LED through RC compensation network - enabling primary-side regulation without secondary-side components.