STMicroelectronics VIPER38LDTR

Overview

VIPER38LDTR from STMicroelectronics is a high-voltage PWM current-mode flyback controller IC integrating an 800 V avalanche-rugged power MOSFET, embedded HV startup generator, and dual-level overcurrent protection (IDlim = 1.15 A typ, IDMAX = 1.7 A). It operates at 60 kHz (L-type) or 115 kHz (H-type), delivers up to 30 W peak power, and achieves 30 mW no-load consumption at 230 Vac - enabling auxiliary power supplies for energy meters and home equipment.

For engineers reviewing the VIPER38LDTR datasheet, VIPER38LDTR pinout, VIPER38LDTR application, or VIPER38LDTR equivalent, key selection criteria include its SDIP10 package thermal performance (R_TH-JC = 5 °C/W), adjustable extra power timer (EPT), jittered oscillator for EMI reduction, and digital noise-filtered output overvoltage protection (VOVP = 3.0 V ±0.3 V).

Technical Context

The VIPER38LDTR implements a current-mode PWM control architecture with integrated 800 V power MOSFET (R_DS(on) = 4.5 Ω @ 25 °C), HV startup sourced from DRAIN pin (V_{DRAIN_START} = 80 V typ), and dual OCP thresholds (IDlim = 1.15 A, IDMAX = 1.7 A) for transformer saturation and secondary diode short-circuit protection.

It features burst-mode operation below V_FBbm = 0.6 V (hysteresis = 90 mV), soft-start time of 8.5 ms, and digitally filtered overvoltage protection strobed at t_STROBE = 2 μs - all coordinated by an internal jittered oscillator (±4 kHz modulation depth for L-type, ±8 kHz for H-type).

Key Specifications

Pinout & Package

Package: SDIP10 (10-pin Small Outline Dual In-line Package with exposed thermal pad); optimized for high-voltage isolation and PCB heat dissipation via DRAIN pins (pins 9–12) connected to metal frame.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ICE3B0565J and LNK364PG, VIPER38LDTR provides superior surge immunity (800 V vs. ≤725 V), precise dual-OCP fault discrimination, and integrated EPT for temporary overload - making it optimal for safety-critical metering and industrial adapters demanding long-term reliability.

Availability

VIPER38LDTR is available at Aetrix Electronics and suitable for auxiliary power supplies, energy meter PSUs, and smart adapters requiring stable component supply, long-lifecycle support, and consistent parametric performance across production batches.

Supply support for VIPER38LDTR 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 sensor solutions for industrial, automotive, and consumer markets.

VIPER38LDTR belongs to the VIPerPlus family of high-voltage AC-DC converters engineered for compact, low-BOM-count offline power supplies targeting energy efficiency standards (DoE Level VI, EU CoC Tier 2) and robust surge immunity.

FAQ

What is the maximum continuous output power achievable with VIPER38LDTR in an open-frame design?

The VIPER38LDTR delivers up to 15 W continuous output power in an open-frame configuration at 50 °C ambient temperature with adequate heat sinking, as verified in ST's DS10100 Rev 3 datasheet Table 1. This assumes SDIP10 mounting on FR4 with ≥100 mm² copper pour for thermal conduction.

How does the EPT (Extra Power Timer) function improve system-level surge handling?

The EPT pin accepts an external capacitor that extends the IC's overload tolerance to ~2 seconds at peak power (30 W), allowing the power supply to sustain brief high-current events such as PLC communication bursts or motor startup surges without shutdown - directly supporting IEC/EN 62368-1 Annex G requirements.

Can VIPER38LDTR operate with a non-isolated buck-derived topology?

No - VIPER38LDTR is specifically designed for isolated flyback topologies with primary-side regulation. Its integrated 800 V MOSFET, DRAIN-referenced startup, and feedback architecture require transformer isolation; it lacks the gate-drive architecture or protection logic needed for buck or buck-boost configurations.

What is the minimum recommended copper area under the DRAIN pins for thermal performance?

STMicroelectronics specifies a minimum 100 mm² copper area (35 μm thick) under DRAIN pins (9–12) to achieve R_TH-JA = 90 °C/W in SDIP10 packages, as documented in Table 4 of DS10100 Rev 3. Smaller copper areas increase junction temperature and risk thermal shutdown under sustained load.