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THS4520: Power Pad electrical Isolation

Howard Bandell
Intellectual 555 points
Part Number: THS4520
Other Parts Discussed in Thread: THS4541

Is the power pad of the THS4520 electrically isolated? do I connect it to ground or Vee?????

  • 0
    Guru 48395 points

    This is the same Howard Bandell that I used to visit at Harris in the early 90's as Comlinear applications manager - who wrote that great design idea to tune CFA flatness with a pot inside the summing loop? 

    You do know Howard, there are considerably more modern FDA's than the THS4520 at this point. It does have a unique pinout, so not drop in upgrade. 

  • 0 in reply to Michael Steffes
    Guru 48395 points

    Hello Howard, 

    I know I am not answering the back metal question, the product group will have to do that - but FYI

    The upgrade to the much older THS4520 is the THS4541 - but not pin compatible (nothing is to that THS4520)

    http://www.ti.com/lit/ds/symlink/ths4541.pdf

    I added this footnote to the pin table, this comes from the process being DI so the back side is electrically isolated from the circuit - I think the THS4520 is the same, but the product group needs to confirm and maybe add this footnote to that older datasheet.

    This is from the THS4541 pin function table. 

  • 0
    TI__Mastermind 29595 points

    Hello Howard,
           The THS4520 is packaged as QFN type which incorporates an exposed thermal pad/PowerPad which is located at the underside of the chip. The PowerPad is a concept where thermal conductive epoxy is used to attach the circuit die to the leadframe of the die pad; there is no electrical connection to the active circuitry in the device making it electrically isolated from the device itself. This type of package requires to be placed and soldered with the exposed pad down onto a PCB board for optimal thermal and mechanical performance. It is recommended to attach the pad to the ground plane since it is the largest metal plane found on the board which maximizes the amount of heat transfer and removal. For more information I have provided links to two tech reports on utilizing the QFN thermally enhanced packaging: SLMA002H SLMA004b SLOA122.