STMicroelectronics EVLSRK1001-TO

Overview

EVLSRK1001-TO from STMicroelectronics is a demonstration board for the SRK1001 adaptive synchronous rectification controller, designed to replace secondary-side diodes in flyback converters. It integrates the FDPF190N15A 150 V / 19 mΩ N-channel MOSFET in TO220FP package, supports up to 500 kHz switching, operates from 3.5–32 V V_CC, and implements fixed turn-on with adaptive turn-off timing.

For engineers reviewing the EVLSRK1001-TO datasheet, EVLSRK1001-TO pinout, EVLSRK1001-TO application, or EVLSRK1001-TO equivalent, this board enables rapid evaluation of QR and FF flyback topologies with configurable blanking (1.44 µs TON, 3 µs TOFF), DVS sensing at 185 V AMR, and remote ON/OFF via DIS/SYNC pin.

Technical Context

The EVLSRK1001-TO implements secondary-side synchronous rectification using the SRK1001 IC, which senses drain-to-source voltage (DVS) to trigger gate drive for the integrated FDPF190N15A MOSFET. Its control logic supports both quasi-resonant (QR) operation-default configuration-and fixed-frequency (FF) mixed DCM-CCM modes, requiring only a 100 pF capacitor at C3 for FF mode.

Blanking timing is resistor-programmable: R3 (120 kΩ) sets TON blanking to 1.44 µs, while R4 (100 kΩ) sets TOFF blanking to 3 µs. The DIS/SYNC pin enables remote enable/disable via an on-board BC847 NPN transistor when zero-ohm R9 is removed.

Key Specifications

Availability

EVLSRK1001-TO is available at Aetrix Electronics and suitable for flyback converter evaluation, QR/FF topology prototyping, and synchronous rectifier replacement in AC-DC adapters, USB PD chargers, and industrial power supplies requiring stable component supply and fast design iteration.

Supply support for EVLSRK1001-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 markets with emphasis on energy efficiency and system integration.

The SRK series targets high-efficiency secondary-side synchronous rectification in isolated AC-DC converters, specifically optimizing flyback topologies for QR and mixed-mode operation with adaptive timing control.

FAQ

What is the primary function of the EVLSRK1001-TO board?

The EVLSRK1001-TO is a demonstration board for evaluating the SRK1001 synchronous rectification controller in flyback converters. It replaces conventional output diodes with the FDPF190N15A MOSFET to reduce conduction losses, improve efficiency, and enable QR or FF operation - all with pre-configured timing and integrated gate drive.

How do I configure the board for fixed-frequency (FF) operation?

To configure for FF operation, install a 100 pF capacitor at position C3. The board ships optimized for quasi-resonant (QR) mode; adding this capacitor modifies the internal oscillator behavior to support fixed-frequency mixed DCM-CCM flyback applications as specified in the SRK1001 datasheet.

Can the DIS/SYNC pin be used for remote control?

Yes - remove zero-ohm resistor R9 to enable the DIS/SYNC pin. The board includes a BC847 NPN transistor connected to this pin, allowing external TTL-level signals to enable or disable synchronous rectification, supporting dynamic load management or system-level power sequencing.

What is the role of the 120 kΩ and 100 kΩ resistors on TON and TOFF pins?

R3 (120 kΩ) sets the TON blanking time to 1.44 µs, preventing false turn-on detection during MOSFET voltage transition. R4 (100 kΩ) sets the TOFF blanking time to 3 µs, suppressing false turn-off triggers caused by parasitic ringing after current zero-crossing - critical for stable operation in noisy flyback environments.