STMicroelectronics VIPER16LDTR

Overview

VIPER16LDTR from STMicroelectronics is an 800 V avalanche-rugged, fixed-frequency off-line PWM controller with integrated high-voltage power MOSFET, designed for low-power AC-DC flyback and buck-boost converters. It operates at 60 kHz, delivers up to 10 W in open-frame designs, supports self-biasing without auxiliary winding, achieves <30 mW standby power at 230 VAC, and integrates adjustable overcurrent limit, soft-start, burst-mode operation, and hysteretic thermal shutdown - enabling compact, energy-compliant auxiliary supplies in smart meters and LED drivers.

For engineers reviewing the VIPER16LDTR datasheet, VIPER16LDTR pinout, VIPER16LDTR application, or VIPER16LDTR equivalent, key selection considerations include its 60 kHz switching frequency, 800 V drain-source breakdown, DIP-7 package with exposed drain pins for thermal management, adjustable current limit via external resistor on LIM pin, and built-in burst mode for sub-30 mW no-load consumption.

Technical Context

The VIPER16LDTR implements a current-mode PWM controller with cycle-by-cycle sensing via integrated SenseFET, enabling precise peak current limiting and stable regulation across line and load variations. Its oscillator features ±4 kHz frequency jittering at 230 Hz to reduce EMI peaks, and burst-mode operation activates when COMP pin voltage falls below 1.1 V, reducing average switching frequency to hundreds of Hz under light loads.

Power delivery is enabled by an internal high-voltage current generator sourcing startup current from the DRAIN pin (40–60 V threshold), followed by self-supply from VDD capacitor during steady state. The device includes open-loop failure protection, safe auto-restart after overload (50 ms timeout, 1 s restart delay), and thermal shutdown at 150–160 °C with 30 °C hysteresis.

Key Specifications

Pinout & Package

VIPER16LDTR is housed in a DIP-7 package with pins 7 and 8 internally connected to the metal frame and externally tied to the DRAIN node for enhanced thermal dissipation. The exposed drain pads require ≥100 mm² copper area beneath for optimal thermal performance (R_thJA = 110 °C/W on standard FR4).

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, VIPER16LDTR uniquely combines 800 V ruggedness, auxiliary-winding-free operation, adjustable current limit, and certified <30 mW standby - making it optimal for space-constrained, energy-regulated auxiliary supplies where reliability under surge and brownout is critical.

Availability

VIPER16LDTR is available at Aetrix Electronics and suitable for smart metering, LED lighting, home appliance control, and industrial sensor power supplies requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for VIPER16LDTR 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.

VIPER16LDTR belongs to the VIPer™ plus family of high-voltage offline controllers, engineered specifically for cost-effective, compact, and energy-efficient AC-DC conversion in sub-15 W auxiliary and primary-side regulated power supplies.

FAQ

What is the minimum input voltage required to start up VIPER16LDTR?

The device initiates startup when the DRAIN pin voltage reaches 40–60 V (typical 50 V), enabling reliable operation even after deep brownouts. This threshold is independent of VDD and ensures consistent turn-on across input voltage dips, provided the bulk capacitor retains sufficient charge to exceed V_{DRAIN_START}.

Can VIPER16LDTR operate without an external feedback network?

Yes - for non-isolated buck or buck-boost topologies delivering 3.3 V, a single resistor from output to FB pin suffices, leveraging the internal 3.3 V reference. For other voltages, an external resistor divider is mandatory; leaving FB floating activates an internal pull-up, preventing latch-up but disabling regulation.

How does the LIM pin adjust overcurrent protection?

Connecting a resistor R_LIM between LIM and GND sinks current proportional to V_{REF_FB/RLIM, scaling the peak drain current limit linearly from 0.4 A down to ~0.1 A. Values >80 kΩ restore default limiting; capacitor ≤470 nF may be added for noise immunity without affecting response time.}

What thermal derating applies when using VIPER16LDTR in DIP-7 package?

At ambient temperatures above 40 °C, power dissipation must be linearly reduced from 1 W (max at T_A ≤ 40 °C) to zero at 105 °C, based on R_thJA = 110 °C/W. A 100 mm² copper pour under pins 7–8 lowers R_thJA to 90 °C/W, extending usable ambient range by ~10 °C at full load.