STMicroelectronics VIPER37HDTR

Overview

VIPER37HDTR from STMicroelectronics is a fixed-frequency offline AC-DC converter IC integrating an 800 V avalanche-rugged N-channel power MOSFET, current-mode PWM controller, dual overcurrent protection (OCP), output overvoltage protection (OVP), brownout detection, and onboard soft-start. It delivers up to 20 W in open-frame designs at 230 VAC and operates at 115 kHz (H-type variant). Used in auxiliary power supplies for ATX systems and low-power adapters.

For engineers reviewing the VIPER37HDTR datasheet, VIPER37HDTR pinout, VIPER37HDTR application, or VIPER37HDTR equivalent, this page provides verified technical context, real-world design meaning of key specs, SO16 narrow package terminal mapping, functional alternatives with documented differences, and supply-chain support for industrial and consumer power design programs.

Technical Context

The VIPER37HDTR implements a current-mode flyback controller with integrated 800 V SenseFET, enabling direct rectified-line operation without external HV startup circuitry. Its oscillator features ±8 kHz frequency jittering at 115 kHz nominal to reduce EMI filter cost, and burst-mode operation below 0.6 V on FB ensures ≤30 mW standby consumption at 265 VAC.

Brownout protection triggers at 0.45 V on BR pin (hysteresis 50 mV), disabling switching until input recovers; thermal shutdown activates at 155 °C (hysteresis 30 °C). Dual OCP includes cycle-by-cycle limiting (1 A typ.) and second-level hiccup-mode protection at 1.7 A, ensuring robust fault recovery in unregulated SMPS topologies.

Key Specifications

Pinout & Package

VIPER37HDTR is housed in a SO16 narrow (SOIC-16) surface-mount package with exposed DRAIN pads (pins 13–16) for enhanced thermal dissipation. The copper area under DRAIN pins must be designed per ST's layout guidelines to achieve R_thJA = 80 °C/W on standard FR4.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar offline AC-DC converter applications.

Compared with VIPER37HDTR, ICE3B0565J offers lower integration and reduced input voltage capability but lower system cost; LNK364PG provides superior safety features and variable-frequency EMI control but sacrifices OCP adjustability and deterministic 115 kHz timing.

Availability

VIPER37HDTR is available at Aetrix Electronics and suitable for ATX auxiliary power supplies, white goods control board PSUs, and DVD player main SMPS requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for VIPER37HDTR 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, MCU, power, and MEMS products for industrial, automotive, and consumer markets.

VIPER37HDTR belongs to the VIPerPlus family of high-voltage offline converters engineered specifically for cost-sensitive, low-to-medium power AC-DC applications where integration, reliability, and regulatory compliance are critical.

FAQ

What is the maximum continuous output power achievable with VIPER37HDTR in a well-heatsinked open-frame design?

VIPER37HDTR delivers up to 20 W continuous output power at 230 VAC in open-frame configurations with adequate heatsinking and ambient temperature ≤50 °C, as validated in ST's reference design AN4175. This assumes proper PCB copper area under DRAIN pins and use of the 115 kHz H-type frequency mode.

How does the CONT pin function in overvoltage protection mode?

When used for OVP, the CONT pin monitors output voltage via an optocoupler feedback network. If voltage exceeds 3.0 V (±0.3 V), the IC enters a digitally filtered, strobed shutdown state with 2.2 µs response time, reducing consumption to 400 µA. Recovery occurs only after fault removal and VDD restart below 4.5 V.

Can VIPER37HDTR operate without an auxiliary winding for VDD supply?

No. While the internal HV startup circuit charges VDD initially via the DRAIN pin, sustained operation requires an auxiliary winding to maintain VDD above 8.5 V. Without it, VDD collapses after soft-start, causing repeated auto-restart cycles and potential thermal stress.

What is the purpose of the BR pin, and how should it be configured if brownout protection is not needed?

The BR pin implements input undervoltage lockout with 0.45 V threshold and 50 mV hysteresis. If unused, ST specifies it must be connected directly to GND to prevent floating input noise from triggering false shutdowns-no pull-up or series resistor is permitted.