STMicroelectronics EVLSRK1004A

Overview

EVLSRK1004A from STMicroelectronics is an evaluation board for the SRK1004A synchronous rectification controller, designed specifically for non-complementary active clamp flyback (NC-ACF) converters in low-side configuration. It integrates the BSC080N12LS-G PowerFLAT 5×6 MOSFET (120 V, 99 A, 9.5 mΩ @ 4.5 V), supports 4–36 V supply, operates up to 500 kHz, and features DVS sensing with 190 V AMR for precise SR timing in high-efficiency AC/DC adapters.

For engineers reviewing the EVLSRK1004A datasheet, EVLSRK1004A pinout, EVLSRK1004A application, or EVLSRK1004A equivalent, this board enables rapid validation of SRK1004A-controlled secondary-side synchronous rectification in NC-ACF topologies - especially where fast turn-off delay (25 ns typ.), logic-level MOSFET drive, and short-circuit detection are critical for efficiency and reliability.

Technical Context

The EVLSRK1004A implements a zero-current-switching (ZCS)-based control scheme: it turns on the SR MOSFET as soon as reverse body diode conduction begins and turns it off near current zero-crossing. This minimizes conduction loss while avoiding shoot-through in NC-ACF architectures.

It supports both low-side and high-side SR configurations, though the board is pre-configured for low-side operation with direct output-voltage supply (VCC = 5.5 V). For high-side use, external auxiliary winding bias and R5 > 47 kΩ are required to enable V_OUT,SC short-circuit detection.

Key Specifications

Availability

EVLSRK1004A is available at Aetrix Electronics and suitable for AC/DC adapter development, USB PD power supply qualification, and industrial offline SMPS design requiring stable component supply, quick-turn evaluation, and production-ready SR implementation.

Supply support for EVLSRK1004A 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, delivering silicon solutions for smart driving, power management, and embedded systems across automotive, industrial, and consumer markets.

The SRK1004x family - including the SRK1004A used on EVLSRK1004A - was engineered to replace diode rectifiers in high-efficiency flyback converters, targeting >94% efficiency in compact, thermally constrained AC/DC applications.

FAQ

What topology is EVLSRK1004A optimized for?

EVLSRK1004A is pre-configured and validated for non-complementary active clamp flyback (NC-ACF) converters operating in low-side synchronous rectification mode. Its layout, component selection (e.g., BSC080N12LS-G MOSFET), and default R5 = 22 kΩ setting align with NC-ACF timing requirements and direct output-voltage biasing.

Can EVLSRK1004A be used in high-side SR configuration?

Yes - the underlying SRK1004A controller supports high-side operation, but EVLSRK1004A requires hardware modification: replace R5 with ≥47 kΩ to enable V_OUT,SC short-circuit detection, and power U1 from an auxiliary winding instead of the output rail to ensure stable VCC during fault conditions.

What is the role of the DVS pin on SRK1004A?

The DVS (drain-to-source voltage) pin monitors the SR MOSFET's V_DS to detect body diode conduction onset and near-zero-current turn-off points. With 190 V AMR, it allows direct sensing without level-shifting, enabling accurate ZCS timing even under high-voltage secondary waveforms typical in universal-input adapters.

Does EVLSRK1004A include protection features beyond short-circuit detection?

Yes - the board implements fast short-circuit detection via the SRK1004A's SCP pin, which triggers immediate gate-drive disable upon overcurrent. Additional safeguards include input decoupling (C1, C2), Schottky clamping diodes (D1–D2), and configurable R5-based V_OUT,SC threshold setting for output-rail fault response.