STMicroelectronics EVL4985-350W

Overview

EVL4985-350W from STMicroelectronics is an evaluation board implementing a continuous conduction mode (CCM) power factor correction (PFC) pre-regulator based on the L4985A controller IC. It delivers regulated 400 Vdc output at 350 W across universal AC input (90–265 Vac, 45–65 Hz), achieves 97.8% peak efficiency, maintains THD <6% at full load, and complies with EN61000-3-2 Class-D and JEITA-MITI Class-D standards for mains harmonics.

For engineers reviewing the EVL4985-350W datasheet, EVL4985-350W pinout, EVL4985-350W application, or EVL4985-350W equivalent, this board serves as a validated reference design for high-efficiency, low-THD PFC stages in industrial SMPS, server power supplies, and telecom rectifiers - enabling rapid prototyping of CCM-PFC front-ends up to several kW.

Technical Context

The EVL4985-350W implements a boost-type CCM PFC topology using the L4985A controller, which integrates an 800 V high-voltage start-up circuit and patented control method to minimize component count and input current distortion. Its design includes active X-capacitor discharge, adaptive zero-current detection, and internal overvoltage/overcurrent protection.

It supports wide-range AC inputs via a bridge rectifier (D3), uses a 700 µH PFC inductor (L1), and regulates output with two parallel 450 V/100 µF electrolytic capacitors (C3, C4). The board features dual heatsinks (HS1, HS2) for the 600 V/36 A MOSFET (Q2) and SiC Schottky diode (D1), ensuring thermal stability under sustained 350 W operation.

Key Specifications

Availability

EVL4985-350W is available at Aetrix Electronics and suitable for industrial SMPS development, telecom rectifier qualification, and server power supply validation requiring stable component supply, traceable BOM sourcing, and long-term design-in support.

Supply support for EVL4985-350W 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, designing and manufacturing analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer applications.

The EVL4985-350W belongs to ST's Power Management Evaluation Board product line, developed to accelerate adoption of high-efficiency CCM-PFC architectures in mid-to-high-power AC-DC conversion systems.

FAQ

What is the primary function of the EVL4985-350W evaluation board?

The EVL4985-350W is a fully assembled, tested reference design that implements a 350 W continuous conduction mode (CCM) power factor correction pre-regulator. It uses the L4985A controller to generate a tightly regulated 400 Vdc output from universal AC input while meeting Class-D harmonic limits - intended for validation and integration into higher-power SMPS front-ends.

Does the board include protection features, and how are they implemented?

Yes - it incorporates overvoltage protection (OVP) via the L4985A's FB pin monitoring, cycle-by-cycle current limiting through the CS pin, and thermal derating enabled by heatsinks on Q2 and D1. The integrated 800 V start-up circuit also provides safe X-capacitor discharge during AC removal, eliminating need for external bleed resistors.

Can the EVL4985-350W be used with non-ST controllers or modified for different output voltages?

No - it is specifically designed around the L4985A controller and its fixed internal reference and gate drive characteristics. Output voltage is set by resistor divider R24/R21 (62 kΩ / 1.22 MΩ) feeding the FB pin and is not user-adjustable without redesigning feedback network and compensating loop stability.

What connectors and test points are provided for system integration and measurement?

The board includes J1 (4-pin screw terminal) for EBM control, GND, and ON/OFF signals; J2 (2-pin screw terminal) for +400 Vdc output; J3 (2-pin screw terminal) for AC input; plus VCC test point and JP1–JP9 jumpers for configuration (e.g., burst-mode enable, soft-start adjustment). All critical nodes are accessible for oscilloscope probing and thermal imaging.