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UCC21750-Q1: Switching unit and gate driver back to back placement on PCB

Part Number: UCC21750-Q1

Hi,

In datasheet of UCC21750-Q1 gate driver, there is description that "No PCB trace or copper is allowed under the gate driver. A PCB cutout is recommended to avoid any noise coupling between the input and output side which can contaminate the isolation barrier"

For UCC21750-Q1 gate driver and TO247 Sic mosfet, in PCB layout is it possible to place a switching unit under the UCC21750-Q1 (placing other side of the PCB) without putting a trace or copper under them. Or how many millimeters is needed between switching unit and PCB not to interfere the gate driver.

Thanks in advance.

  • Hi,

    Our expert is out of office for the remainder of the week. He will get back to you with an update mid next week. 

    Regards,

    Krystian

  • Hi Ismail, 

    Apologize for any delay in response. 

    it should be OK to place a second driver exactly underneath the first driver on top of board. The purpose of our recommendation to not route any traces between the planes is to not reduce creepage / clearance, which would reduce the isolation efficacy. 

    If this is your plan, please be certain to align both drivers so there is no overlap between ground planes or signals. Also make sure to strongly connect by vias the top and bottom ground planes. 

    Please let usknow if you have any additional questions.

    Best

    Dimitri

  • Hi Dimitri,

    Thank you for your answer. I want to clarify my question. Is it possible to place sic mosfet (TO-247) under the gate driver (placing other side of the PCB such that placing gate driver top side and mosfet bottom side of the PCB). 

    Best regards.

    Thanks.

  • Ismail, 

    Yes that is OK. WIth a to247 you can route the OUT on just one layer without via which is what we recommend. 

    If this answers your questions please let me know by pressing the green button. 

    Best

    Dimitri