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UCC28702: IC failure during Electrical fast transient test

Part Number: UCC28702

Tool/software:

Hi,

I am facing a issue in my power supply section, the UCC28702 flyback IC is failing during EFT(bust) test.

The IC is failing during 4KV, P-N at 5KHz level. The IC is flikering for 4 to 5 times and totaly going dead.

Remaining all voltage levels like 500V, 1KV and 2 KV it is passing.

The test is conducted as per IEC 61000-4-4. 

Need your help on this issue.

  • Hi Yogendra,

    Thank you for reaching out.

    I think this could be an issue of the transient coupling to the controller and potentially causing damage. I would recommend checking the layout. With the very short rise times exhibited by EFT pulses, any antenna effect has the capability of receiving high voltage spikes. Shorter lines reduce the level of radiated energy received and lower the spikes resulting from electrostatic discharges. This will also keep both resistive and inductive effects to a minimum. All traces carrying high currents, especially if pulsed (tracks of the power loops), should be as short and wide as possible. Power and control ground should be decoupled at the bulk capacitor to avoid high frequency noise interfering with the control signals. Ensure these are optimized in your layout.

    Let us know if you have any questions.

    Regards,

    Harish