STMicroelectronics EVLSRK1000A-TO

Overview

EVLSRK1000A-TO from STMicroelectronics is a demonstration board for the SRK1000A adaptive synchronous rectification controller, designed to replace secondary-side diodes in flyback converters. It integrates the SRK1000A IC and an 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.

For engineers reviewing the EVLSRK1000A-TO datasheet, EVLSRK1000A-TO pinout, EVLSRK1000A-TO application, or EVLSRK1000A-TO equivalent, this board enables rapid evaluation of QR and fixed-frequency flyback SR performance, gate-drive timing behavior, blanking window configuration (0.8 µs via R5), and MOSFET substitution feasibility in existing power supplies.

Technical Context

The EVLSRK1000A-TO implements the SRK1000A's fixed turn-on + adaptive turn-off control scheme optimized for secondary-side synchronous rectification in flyback topologies. It supports both quasi-resonant (QR) operation out-of-box and fixed-frequency (FF) mixed DCM-CCM mode with a single 100 pF capacitor addition at C4.

Board-level design includes internal gate drive for high-current N-MOSFET switching, 68 kΩ pull-up on TON pin for 0.8 µs blanking, and direct integration of the STF80N10F7 MOSFET - eliminating external layout dependencies for gate drive loop integrity and voltage sensing path.

Key Specifications

Availability

EVLSRK1000A-TO is available at Aetrix Electronics and suitable for AC-DC adapter development, USB PD fast-charging reference design validation, and industrial flyback power supply efficiency certification requiring stable component supply and documented SR implementation.

Supply support for EVLSRK1000A-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, delivering silicon solutions for automotive, industrial, power, and digital consumer applications with emphasis on energy efficiency and system integration.

The SRK series targets high-efficiency secondary-side synchronous rectification in isolated AC-DC converters, specifically addressing thermal and EMI challenges in compact flyback power supplies.

FAQ

Is EVLSRK1000A-TO a standalone power supply?

No. EVLSRK1000A-TO is not a complete power supply. It is a demonstration board that provides only the synchronous rectifier stage - including the SRK1000A controller and STF80N10F7 MOSFET - intended for integration into an existing flyback converter to replace the secondary-side diode. Primary-side control and transformer remain external.

What modifications are needed to use EVLSRK1000A-TO in fixed-frequency flyback designs?

To operate in fixed-frequency (FF) mode, a 100 pF capacitor must be soldered at position C4 on the board. This modifies the adaptive turn-off timing circuit to accommodate constant switching frequency waveforms. No changes to R5 or other components are required for baseline FF operation.

Can the STF80N10F7 MOSFET on EVLSRK1000A-TO be replaced with another device?

Yes, but only with caution. The board's gate drive and layout are optimized for the STF80N10F7's capacitance and threshold characteristics. Substitution requires verifying Qg, Ciss, and VGS(th) compatibility, re-evaluating gate resistor values, and validating noise immunity - especially during DVS transitions above 60 V.

Does EVLSRK1000A-TO support continuous conduction mode (CCM) operation?

Yes - the SRK1000A controller on this board supports mixed DCM-CCM operation in fixed-frequency flyback applications. However, the default board configuration is tuned for QR operation; CCM functionality requires enabling FF mode via C4 and confirming transformer reset behavior and current-sense signal integrity under full-load conditions.