STMicroelectronics EVLSRK1000A-PF

Overview

EVLSRK1000A-PF from STMicroelectronics is a demonstration board for evaluating the SRK1000A adaptive synchronous rectification controller in flyback converters, featuring fixed turn-on/adaptive turn-off timing, 3.5–32 V VCC range, 90 V max DVS rating, 500 kHz max switching frequency, and integrated gate drive for N-channel logic-level MOSFETs (FDMS86103L, 100 V / 12 mΩ, PowerFLAT 5×6).

For engineers reviewing the EVLSRK1000A-PF datasheet, EVLSRK1000A-PF pinout, EVLSRK1000A-PF application, or EVLSRK1000A-PF equivalent, this board enables rapid validation of secondary-side synchronous rectification in QR and FF flyback topologies with minimal hardware modification and configurable blanking time via R5 (68 kΩ) and optional C4 (100 pF).

Technical Context

The EVLSRK1000A-PF implements the SRK1000A controller's proprietary adaptive turn-off algorithm that senses drain-to-source voltage (V_DS) crossing to minimize conduction loss while avoiding shoot-through in quasi-resonant (QR) flyback operation. It supports both QR and fixed-frequency (FF) mixed DCM-CCM modes, with default configuration optimized for QR.

Board-level design includes direct integration of the FDMS86103L PowerFLAT 5×6 MOSFET, internal gate driver capable of ±1.5 A peak current, and TON pin biasing (R5 = 68 kΩ) setting blanking time to ~0.8 μs - critical for noise immunity during MOSFET turn-on transients.

Key Specifications

Availability

EVLSRK1000A-PF is available at Aetrix Electronics and suitable for USB PD adapters, industrial AC/DC power supplies, and consumer wall adapters requiring stable component supply and fast evaluation of synchronous rectification performance.

Supply support for EVLSRK1000A-PF 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, designing and manufacturing microcontrollers, power ICs, analog devices, and silicon solutions for industrial, automotive, and consumer markets.

The SRK series targets high-efficiency secondary-side synchronous rectification in isolated AC/DC converters, specifically optimizing efficiency and EMI in QR and FF flyback topologies across 5 W to 100 W applications.

FAQ

What is the primary function of the EVLSRK1000A-PF board?

The EVLSRK1000A-PF is a dedicated evaluation platform for the SRK1000A synchronous rectifier controller. It enables engineers to validate adaptive turn-off behavior, measure efficiency gains over diode rectification, and assess thermal performance using the integrated FDMS86103L MOSFET in real flyback converter implementations - not a production-ready power stage.

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

To operate in fixed-frequency mode, install a 100 pF capacitor at position C4 on the board. This modifies the internal timing network to enable FF-compatible adaptive turn-off detection. The default configuration (C4 unpopulated) is optimized for quasi-resonant (QR) operation.

Can the EVLSRK1000A-PF replace a standard rectifier diode directly in an existing flyback design?

Yes - the board is designed for drop-in replacement of secondary-side diodes. Its compact layout, pre-mounted FDMS86103L MOSFET, and compatible pinout allow integration into existing transformer secondaries with minimal PCB rework, provided V_DS stress remains ≤90 V and gate drive loop inductance is minimized.

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

R5 sets the blanking time after MOSFET turn-on to approximately 0.8 μs. This prevents false turn-off triggered by V_DS ringing during switching transitions, ensuring reliable synchronous rectification under high dv/dt conditions typical in QR flyback operation.