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CSD19534Q5A: PCB layout

Part Number: CSD19534Q5A

Hi team,

 

Please kindly advise the below.

 

-       Why is between 5 and 8 pin placed not only bottom but also lateral ?

-       Is solider fillet mandatory ? There is no problem if the bottom side is mounted ?

-       If solider fillet is mandatory, are there any conditions for solider filet ? It is ok to follow the datasheet ?

-       Are there any problem if solider bridge is seen between 5 pin and 8 pin ?

-       Are there any problem if via is placed at bottom for drain

 

Thank you and best regards,

Michiaki

  • Hi Michiaki san,

    Thanks for the questions. I have consulted with packaging/SMT expert and our responses are as follows:

    • I think you are asking about the extensions of the thermal pad on either side of the package. This is because we want to cover all solderable area under the package and maintain good bond line thickness of solder.
    • See link below to the app note: QFN and SON PCB Attachment (SLUA271B) states that IPC-A610D does not require a side fillet, since the side terminations are not plated.
    • Solder fillet is not mandatory.
    • This shouldn’t be a problem since they are electrically common to the drain. Care should be taken to avoid bridging between pin 3 (source) and pin 4 (gate).
    • No, as long as via is a tented or plugged via to prevent solder flow into or though the via during reflow. Vias in the drain pad helps to improve thermal performance.