STMicroelectronics EVLSRK1000B-TO

Overview

EVLSRK1000B-TO from STMicroelectronics is a demonstration board for the SRK1000B adaptive synchronous rectification controller, designed to replace secondary-side diodes in flyback converters. It integrates the STF80N10F7 100 V / 10 mΩ N-channel MOSFET in TO-220FP package, supports up to 500 kHz switching, operates with VCC from 3.5 V to 32 V, and handles DVS up to 90 V in quasi-resonant (QR) configurations.

For engineers reviewing the EVLSRK1000B-TO datasheet, EVLSRK1000B-TO pinout, EVLSRK1000B-TO application, or EVLSRK1000B-TO equivalent, this board enables rapid evaluation of adaptive turn-off SR control in QR flyback topologies, gate-drive capability for high-current N-MOSFETs, and layout integration into existing AC/DC adapters and USB PD power supplies.

Technical Context

The EVLSRK1000B-TO implements fixed turn-on timing with adaptive turn-off based on drain-voltage sensing, enabling efficient operation across variable load and input conditions in QR flyback converters. It supports both QR and fixed-frequency (FF) mixed DCM-CCM modes, with FF mode requiring addition of a 100 pF capacitor at C4.

It features an internal gate driver optimized for driving the STF80N10F7 MOSFET, includes a 68 kΩ resistor on the TON pin setting blanking time to ~0.8 μs, and accepts VCC supply from 3.5 V to 32 V while tolerating up to 90 V on the DVS pin during transient events.

Key Specifications

Availability

EVLSRK1000B-TO is available at Aetrix Electronics and suitable for AC/DC adapter development, USB PD power supply qualification, and industrial flyback converter optimization requiring stable component supply and validated reference implementation.

Supply support for EVLSRK1000B-TO 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, delivering microcontrollers, power ICs, analog devices, and silicon solutions for automotive, industrial, and consumer markets.

The SRK1000B product line targets high-efficiency secondary-side synchronous rectification in isolated flyback converters, specifically addressing efficiency compliance (e.g., DOE VI, CoC Tier 2) and thermal reduction in compact power adapters.

FAQ

What is the primary function of the EVLSRK1000B-TO board?

The EVLSRK1000B-TO is a demonstration board for evaluating the SRK1000B synchronous rectifier controller in flyback converters. It replaces conventional secondary-side diodes with the STF80N10F7 MOSFET and implements adaptive turn-off control to reduce conduction losses and improve efficiency above 75% load.

Can the EVLSRK1000B-TO be used in fixed-frequency flyback designs?

Yes - the board supports fixed-frequency (FF) mixed DCM-CCM operation. To enable FF mode, a 100 pF capacitor must be added at position C4 per the schematic. The default configuration is optimized for quasi-resonant (QR) applications.

What is the role of the 68 kΩ resistor (R5) on the TON pin?

R5 sets the blanking time after turn-on to approximately 0.8 μs, preventing false turn-off triggering due to gate-drain capacitance ringing or noise during MOSFET turn-on transitions. This ensures robust operation under high dv/dt conditions typical in flyback secondaries.

How is thermal performance managed on the EVLSRK1000B-TO board?

The STF80N10F7 MOSFET is mounted in a TO-220FP package with exposed drain pad, allowing direct heatsink attachment. The board layout provides copper pour and thermal vias beneath the MOSFET footprint to enhance heat dissipation, supporting continuous operation at ≥8 A output current in properly heatsinked adapters.