STMicroelectronics EVL400W-EUPL7

Overview

EVL400W-EUPL7 from STMicroelectronics is a 12 V / 33 A (400 W) AC/DC evaluation board implementing a two-stage architecture: continuous-conduction-mode (CCM) boost PFC using the L4984D controller, and an LLC resonant half-bridge DC/DC stage driven by the L6699D, with synchronous rectification via SRK2001. It targets high-efficiency external power supplies for computing and industrial equipment.

For engineers reviewing the EVL400W-EUPL7 datasheet, EVL400W-EUPL7 pinout, EVL400W-EUPL7 application, or EVL400W-EUPL7 equivalent, this board serves as a validated reference design for 80 PLUS Platinum/Gold-compliant 12 V adapters requiring ultra-low no-load consumption (<150 mW), >89% average efficiency per CoC v5 Tier 2, and EN61000-3-2 Class-D harmonic compliance.

Technical Context

The board implements a front-end CCM boost PFC stage controlled by the L4984D using line-modulated fixed-off-time (LM-FOT) methodology, enabling stable fixed-frequency operation across universal input (90–264 Vac). The downstream LLC resonant converter uses the L6699D double-ended controller to regulate output voltage via variable-frequency modulation of the half-bridge switching nodes.

Secondary-side synchronous rectification is managed by the SRK2001, which drives four STL140N6F7 MOSFETs to minimize conduction losses. Light-load efficiency is optimized through coordinated burst-mode operation in both PFC and LLC stages, plus self-adaptive deadtime control in the L6699D that reduces primary current at low loads by maximizing transformer magnetizing inductance.

Key Specifications

Availability

EVL400W-EUPL7 is available at Aetrix Electronics and suitable for server power supply validation, industrial AC/DC adapter development, and energy-efficient computing equipment requiring stable component supply and pre-validated topology implementation.

Supply support for EVL400W-EUPL7 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, analog devices, and discrete components for automotive, industrial, and consumer markets.

This board belongs to ST's Industrial Offline Power Supply Business Unit portfolio, developed specifically to accelerate time-to-market for high-efficiency, standards-compliant AC/DC converters targeting 80 PLUS Platinum, CoC Tier 2, and EN61000-3-2 regulatory requirements.

FAQ

What is the primary purpose of the EVL400W-EUPL7 evaluation board?

The EVL400W-EUPL7 is a fully assembled, tested reference design for a 400 W, 12 V AC/DC adapter. It demonstrates ST's two-stage architecture-CCM boost PFC (L4984D) followed by LLC resonant conversion (L6699D) with synchronous rectification (SRK2001)-to achieve 80 PLUS Platinum/Gold certification, ultra-low no-load power, and full compliance with EN61000-3-2 Class-D and EN55022 Class-B standards.

Which ST controllers are integrated on the EVL400W-EUPL7, and what are their roles?

The board integrates three key ST controllers: the L4984D manages the front-end CCM boost PFC stage using LM-FOT control; the L6699D drives the LLC resonant half-bridge with adaptive deadtime and frequency modulation for precise 12 V regulation; and the SRK2001 controls four STL140N6F7 MOSFETs on the secondary side to replace Schottky diodes and improve light-load efficiency.

Does the EVL400W-EUPL7 support universal AC input, and how is efficiency maintained across voltage ranges?

Yes, it accepts 90–264 Vac input. Efficiency is sustained across both 115 Vac and 230 Vac lines via topology-level optimization: the L4984D's LM-FOT ensures stable PFC operation over wide input, while the L6699D's variable-frequency LLC control maintains tight regulation and low losses. Measured average efficiency exceeds 89% at both voltages, meeting 80 PLUS Platinum (115 Vac) and Gold (230 Vac) requirements.

Can the EVL400W-EUPL7 be modified for different output voltages or power levels?

The board is optimized for 12 V / 400 W and is not field-configurable for other outputs. Altering output voltage would require redesigning the LLC transformer turns ratio, feedback divider (TLVH431AIL3T-based), gate drive timing, and synchronous rectifier timing-none of which are user-adjustable via jumpers or potentiometers. ST provides design files and schematics to support derivative development, but the evaluation board itself is fixed-function.