STMicroelectronics EVLSTCH03-36W-SR

Overview

EVLSTCH03-36W-SR from STMicroelectronics is a 36 W USB charger demonstration board implementing a quasi-resonant flyback topology with selectable 5 V / 9 V / 12 V output at 3 A continuous current, based on the STCH03L primary-side controller and SRK1000B synchronous rectifier driver. It delivers CV/CC regulation, achieves <20 mW no-load consumption, complies with EuP CoC v5 Tier 2 and EN55022 Class B EMI, and targets compact AC-DC adapter designs.

For engineers reviewing the EVLSTCH03-36W-SR datasheet, EVLSTCH03-36W-SR application, EVLSTCH03-36W-SR evaluation board layout, or EVLSTCH03-36W-SR reference design integration, this page provides verified functional context, efficiency data across load/voltage points, synchronous rectification timing behavior, and regulatory compliance evidence for rapid prototyping and qualification of multi-voltage USB power supplies.

Technical Context

The board implements a peak-current-mode-controlled quasi-resonant flyback converter using the STCH03L IC, which integrates a 650 V HV startup cell and burst-mode management to enable <20 mW no-load input power. Constant voltage regulation is achieved via optocoupler feedback, while constant current regulation uses primary-side sensing-eliminating secondary shunt components.

At the secondary side, the SRK1000B drives a synchronous rectifier MOSFET with adaptive turn-off timing to limit body-diode conduction to ≤300 ns, directly improving light-load and full-load efficiency. The design meets Eu CoC v5 Tier 2 (88.3% avg. efficiency minimum) and DOE EPS requirements across 5–12 V outputs and 115/230 VAC inputs.

Key Specifications

Availability

EVLSTCH03-36W-SR is available at Aetrix Electronics and suitable for USB PD-adjacent adapter development, multi-voltage industrial charging stations, and energy-compliant consumer electronics requiring stable component supply and validated reference designs.

Supply support for EVLSTCH03-36W-SR 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 chips, and silicon solutions for automotive, industrial, and consumer applications.

This evaluation board belongs to ST's STCH03L/SRK1000B ecosystem for high-efficiency, low-noise, multi-output AC-DC converters targeting USB charging, IoT power supplies, and compact offline SMPS designs.

FAQ

What output voltages does the EVLSTCH03-36W-SR support, and how is selection implemented?

The board supports three fixed output voltages: 5 V, 9 V, and 12 V, each delivering up to 3 A continuously. Selection is performed via external jumpers or solder bridges on the PCB - no software or digital interface is required. Each configuration routes dedicated feedback paths to the STCH03L controller, enabling precise CV regulation per voltage level as verified in Figures 2–4 of the DB3823 data brief.

How does the SRK1000B improve efficiency compared to standard diode rectification?

The SRK1000B drives a synchronous rectifier MOSFET with adaptive gate timing that minimizes body-diode conduction time to ≤300 ns after turn-off. This reduces conduction losses significantly - especially at light loads - contributing directly to measured efficiencies exceeding Eu CoC v5 Tier 2 requirements across all output voltages and input conditions.

Does the EVLSTCH03-36W-SR include constant current (CC) regulation, and how is it achieved?

Yes - the board provides true constant current regulation during CC mode (e.g., battery charging). It uses primary-side sensing with the STCH03L, eliminating the need for a secondary-side current-sense resistor or shunt. This simplifies BOM, improves reliability, and maintains accuracy within ±5% over line/load/temperature as confirmed by CV-CC transition waveforms in Figures 2–4.

Is the EVLSTCH03-36W-SR RoHS compliant and certified for commercial deployment?

Yes - the board is RoHS compliant (per DB3823 Rev 1 description) and designed to meet EN55022 Class B conducted EMI limits and EuP CoC v5 Tier 2 efficiency standards. While it is a demonstration board and not a certified end-product, its validated performance and layout serve as a foundation for CE/FCC-certifiable designs when implemented per ST's recommended layout and safety clearances.