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TPS549D22: Schematic review

Part Number: TPS549D22


My customer wants to use the TPS549D22 with the following conditions:

    * PVIN=12V / VOUT=0.85V / Switching frequency : 650KHz

    * Normal operation under the above conditions without PMBus control

Could you please review the attached circuit design?


Thank you.


  • Hi JH,

    I have the following feedback regarding the schematic:

    1. I would recommend a lower capacitance for C25. 0.1uF or 0.22uF rated for 25V is sufficient for this application

    2. The value for R57 may need to be changed to maximize the effectiveness of the RC snubber. This can also be left as do not populate if the snubber will be adjusted following initial testing

    3. Pin 32 (ADDR) does not support a resistor divider. Please refer to table 4 in the datasheet for the address select options. In the case that R49 were left unpopulated, this would select FCCM operation and PMBus address 0010000b

    Other than that, the remainder of the schematic looks good to me.


    Alec Biesterfeld

  • Hi Alec,

    Thanks for your reply.

    As per your comment #3, Pin 32 (ADDR) does not support a resistor divider. 

    However, in the webench or datasheet, a resistor divider is used as shown below.

     1. Webench                                                                         2. Datasheet

    Does this depend on whether PMBus control is used or not?

    Which ADDR pin connection matches the customer's intention to use the TPS549D22 without PMBus control?



  • Hi JH, 

    If the customer intends to use the TPS549D22 without PMBus control, then the resistor configuration on the ADDR pin does not matter. In that case, I would suggest leaving the resistors unpopulated to save on the BOM cost.


    Alec Biesterfeld