STMicroelectronics EVLSRK1000B-PF

Overview

EVLSRK1000B-PF from STMicroelectronics is a demonstration board for the SRK1000B adaptive synchronous rectification controller, designed to replace secondary-side diodes in flyback converters. It integrates a fixed-turn-on/adaptive-turn-off control scheme, supports up to 500 kHz switching frequency, operates with VCC from 3.5 V to 32 V, and includes an FDMS86103L 100 V / 12 mΩ logic-level N-channel MOSFET in PowerFLAT 5×6 package for QR-mode evaluation.

For engineers reviewing the EVLSRK1000B-PF datasheet, EVLSRK1000B-PF pinout, EVLSRK1000B-PF application, or EVLSRK1000B-PF equivalent, this board enables rapid validation of SRK1000B's gate-drive timing, DVS voltage handling (≤90 V), blanking configuration (0.8 μs via R5), and QR vs. fixed-frequency mode adaptation (C4 modification).

Technical Context

The EVLSRK1000B-PF implements the SRK1000B IC's secondary-side synchronous rectification logic optimized for flyback topologies. It supports both quasi-resonant (QR) and fixed-frequency (FF) mixed DCM-CCM operation, with factory-set QR configuration and a documented C4 capacitor addition path (100 pF) for FF use.

It features internal high-current gate drive for N-channel MOSFETs, 3.5–32 V VCC supply range, and 90 V max DVS rating - enabling direct integration into existing flyback designs without auxiliary bias winding redesign. The included FDMS86103L MOSFET is rated at 100 V and 12 mΩ R_DS(on), packaged in PowerFLAT 5×6.

Key Specifications

Availability

EVLSRK1000B-PF is available at Aetrix Electronics and suitable for flyback converter design validation, QR-mode power adapter qualification, and synchronous rectifier efficiency benchmarking requiring stable component supply and documented reference implementation.

Supply support for EVLSRK1000B-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, delivering microcontrollers, power management ICs, analog chips, and discrete devices for industrial, automotive, and consumer applications.

The SRK1000B product line targets high-efficiency secondary-side synchronous rectification in AC-DC flyback converters, specifically addressing thermal and conduction loss reduction in USB PD, industrial SMPS, and low-noise offline adapters.

FAQ

What is the primary purpose of the EVLSRK1000B-PF board?

The EVLSRK1000B-PF is a ready-to-use demonstration board for evaluating ST's SRK1000B synchronous rectification controller in flyback converters. It includes all necessary components - controller, gate driver, and FDMS86103L MOSFET - pre-configured for quasi-resonant operation, allowing immediate substitution of diode rectifiers to measure efficiency gains and thermal performance.

Can EVLSRK1000B-PF be used in fixed-frequency flyback designs?

Yes - the board ships configured for quasi-resonant (QR) mode, but supports fixed-frequency (FF) operation by adding a 100 pF capacitor at position C4. This modifies the adaptive turn-off behavior to align with constant-frequency control schemes while retaining the SRK1000B's core timing and blanking functions.

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

R5 sets the turn-on blanking time to approximately 0.8 μs, preventing false triggering caused by drain voltage ringing immediately after primary switch turn-off. This ensures reliable MOSFET turn-on only after parasitic oscillations settle, critical for stable operation across varying load and input conditions.

Does EVLSRK1000B-PF require an external gate driver or level shifter?

No - the SRK1000B IC on the board provides integrated high-current gate drive optimized for logic-level N-channel MOSFETs. The included FDMS86103L has a 2.5 V threshold and is fully compatible with the controller's 5 V gate output, eliminating need for external drivers or level shifters in typical 5–24 V output applications.