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THS4141: THS4141 Recommended Exposed Pad Connection

Kevin Wood
Prodigy 50 points
Part Number: THS4141
Other Parts Discussed in Thread: THS4140

Hi,

The datasheet for the THS4141 says "The thermal pad is electrically isolated from all terminals in the package."

I cannot find anywhere the recommended electrical connection for the exposed pad on this chip.  It would benefit my thermal performance greatly if I can connect this to an existing internal plane (+ supply, - supply, or ground), but I don't want to introduce performance degradation.  I know that some amplifier IC's require the thermal pad to be connected to V- for biasing purposes.  I have been using this chip in this application for 3+ years without connecting the thermal pad to any significant amount of copper but it is roasting hot.  Is there a recommended electrical connection for this that would allow me to tie it to a power plane, or is that just to leave the exposed pad net floating?  Adding an external heat sink is not an option as there is no room.

  • +1
    TI__Mastermind 24965 points

    Hello Kevin,

      Correct, connecting the exposed pad of the chip to a thermal dissipative plane via copper area underneath the package would achieve best thermal performance. Also, yes it is common practice to connect to either ground or VS- in most of our devices, but as you mentioned, some devices might explicitly state not to make an electrical connection. 

      In the above snippet of the section in the datasheet, it states that: "through the use of thermal paths within this copper area, heat can be conducted away from the package into either a ground plane or other heat dissipating device". Also, the THS4140EVM connects the device's thermal pad to the ground plane. Therefore, the device can be tied to your ground plane. 

    Thank you,

    Sima 

  • 0 in reply to SimaJalaleddine
    Prodigy 50 points

    Perfect - thank you for this answer and clarification.  I did check the gerbers, but perhaps I didn't see the vias overlaid on the copper when it was loaded.