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UCC28781-Q1: XCD and P13 pins when only DC input is used

Part Number: UCC28781-Q1
Other Parts Discussed in Thread: UCC28781EVM-053

HI TI,

We are building a board based on UCC28781EVM-053 where only DC input is used.- Does that mean we should not include the marked block, also ground the XCD signal? 

Thank you,

Valentinas P

  • Hello Valentinas, 

    Yes, you are correct.  For DC-only input, there is no need for the components within the red box that you have marked.  XCD inputs should be connected to AGND. 
    In addition, there is no need for any of the AC-input components directly above the marked red box, up to and including the J2 connector, although some EMI filtering may be necessary, depending on your application. 

    You may also need to consider DC fusing and input polarity protection (input diode), if there is any possibility of reverse connection or primary short circuit. 

    Regards,
    Ulrich