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adding a thermal pad to top of DAC5688IRGCR

Phil Dwenger
Prodigy 40 points
Other Parts Discussed in Thread: DAC5688

Our end customer is putting .125" thermal pad on the top of the DAC5688IRGCR to help dissipate the heat.  Is this acceptable, or does it do more harm than good?

  • 0
    TI__Guru* 78404 points

    Hi Phil,

    How are they implementing the .125'' thermal pad on the top of the DAC5688? Is the top thermal pad used in conjunction with a heatsink or active cooling? Please let me know so I can ask the package team for advice. 

    Most of the time, the bottom thermal pad may be sufficient for thermal dissipation if the thermal pad is designed with sufficient copper area and thickness. The customer may refer to our DAC5688 EVM design package for reference design of the thermal pad area and board stack-up. This method may reduce design time and cost. 

    -KH. 

  • 0 in reply to Kang Hsia
    Prodigy 40 points

    Yes, the top thermal pad is used in conjunction with a large heatsink that spams the length of the pcb. 

  • 0 in reply to Phil Dwenger
    TI__Guru* 78404 points

    Hi Phil,

    sorry for the delay. This is feedback I have received from the packaging group today:

    We have seen customer placing external heat sink on top of the QFN packages using a thermal interface material. Key considerations doing this are as follows.

    • Thermal conductivity of the thermal interface material
    • Heat sink mounting to the PCB board – make sure that this is not putting a lot of pressure on the TI part since this can impact the package performance/integrity

     

      If the customer can increase the Cu thickness / % coverage on the PCB board that would be best. Another is if they can move the TI part towards the center of the PCB that can help dissipate heat as compared if this is located on the corner of the board.

    -KH