STMicroelectronics VIPER17LDTR

Overview

VIPER17LDTR from STMicroelectronics is a high-voltage 800 V avalanche-rugged flyback controller IC with integrated power MOSFET, operating at 60 kHz (L-type), delivering up to 5 W in open-frame and 9 W in enclosed adapters, featuring adjustable current limit via CONT pin, <30 mW standby power at 265 VAC, and on-board soft-start for PDA/phone/LED driver auxiliary supplies.

For engineers reviewing the VIPER17LDTR datasheet, VIPER17LDTR pinout, VIPER17LDTR application, or VIPER17LDTR equivalent, key selection considerations include its SO16 narrow package thermal resistance (RthJA = 80 °C/W on FR4), burst-mode operation at light load, brown-out protection with 0.45 V threshold, and dual-level overcurrent protection with hiccup mode recovery.

Technical Context

The VIPER17LDTR integrates an 800 V N-channel SenseFET with 24 Ω typical RDS(on) at 25 °C and implements current-mode PWM control with leading-edge blanking (300 ns), minimum ON time (220 ns), and jittered oscillator (±4 kHz spread at 250 Hz) to reduce EMI filter cost. Its HV startup circuit draws current directly from DRAIN, eliminating external bias winding during startup.

Control logic includes digitally filtered OVP strobing (2.2 µs delay), hysteresis-based thermal shutdown (155 °C trip, 30 °C hysteresis), and dual OCP: primary cycle-by-cycle limit (0.4 A typ.) adjustable via RLIM resistor, plus secondary fixed 0.6 A hiccup-mode threshold. The CONT pin serves dual roles - current limit tuning and output voltage monitoring - with digital filtering for noise immunity.

Key Specifications

Pinout & Package

VIPER17LDTR uses the SO16 narrow (SOIC-16) surface-mount package with exposed thermal pad connected to pins 13–16 (DRAIN). The package provides 80 °C/W junction-to-ambient thermal resistance on standard FR4 with 100 mm² copper pour, enabling 5 W continuous output in open-frame designs without forced air.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ICE2QS03G and LNK306P, VIPER17LDTR offers superior EMI suppression via frequency jitter, tighter OVP accuracy with digital strobing, and direct current limit tuning - making it optimal for compact, certified adapters where layout space and regulatory margin are critical.

Availability

VIPER17LDTR is available at Aetrix Electronics and suitable for smartphone adapters, PDA chargers, LED driver auxiliary supplies, and set-top box standby PSUs requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for VIPER17LDTR 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, microcontroller, power, and sensor solutions for automotive, industrial, and consumer markets.

VIPER17 belongs to ST's VIPerPlus high-voltage offline controller family, engineered specifically for cost-sensitive, space-constrained flyback converters in universal-input AC/DC adapters and auxiliary power supplies.

FAQ

What is the purpose of the CONT pin on VIPER17LDTR?

The CONT pin serves two verified functions: (1) adjusting the cycle-by-cycle current limit threshold via an external resistor (RLIM), scaling IDLIM from 0.38 A to 0.42 A; and (2) monitoring auxiliary winding voltage for overvoltage protection using a digitally filtered, strobed sampling window (2.2 µs delay). It must be decoupled with a 100 nF capacitor to ground for noise immunity.

How does VIPER17LDTR achieve <30 mW standby power?

VIPER17LDTR achieves sub-30 mW no-load consumption through burst-mode operation (triggered when FB voltage falls below 0.45 V), ultra-low quiescent current (270 µA in UVLO state), and automatic shutdown of the HV startup generator once VDD reaches 14 V. These features eliminate auxiliary winding bias current and minimize switching losses during idle periods.

Can VIPER17LDTR replace VIPER17LN in existing DIP-7 designs?

No - VIPER17LDTR uses SO16 narrow packaging with different pinout, thermal characteristics (RthJA = 80 °C/W vs. DIP-7's 110 °C/W), and PCB footprint. While electrical functionality is identical to VIPER17LN (both L-type, 60 kHz), the SO16 package requires redesign of layout, thermal pads, and solder stencil - it is not a drop-in replacement.

What is the role of the BR pin and how should it be configured?

The BR pin implements brown-out protection by monitoring a scaled version of the rectified input voltage. When BR voltage falls below 0.45 V, the device shuts down non-latching to prevent unstable regulation. If unused, BR must be tied directly to GND; floating the pin causes undefined behavior and potential malfunction during low-line conditions.