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LMK04714-Q1: Thermal performance without exposed pad connection (socket use)

Kevin Chen
Prodigy 10 points

Part Number: LMK04714-Q1

Hello,

I am reviewing the LMK04714-Q1 for a use case where the device will not be soldered directly to a PCB. This is not strictly related to clock and timing, but this is the only forum that exists for the LMK04714-Q1.

From the datasheet, it appears that the thermal specifications (e.g., theta-ja) assume standard PCB mounting with the exposed pad soldered to a thermal land.

In our application, the device would instead be placed in a test socket, and the exposed pad would not be connected to a conductive thermal path. The device would be powered (DC biased) for extended durations (24–36 hours), with minimal switching activity.

Do you have any guidance on thermal behavior in this configuration, such as:

  • Expected degradation in theta-ja without exposed pad connection
  • Any recommendations for thermal management in socketed operation
  • Whether operation under these conditions is within reasonable use, assuming junction temperature limits are maintained

Thank you for your time and support!

Best,
Kevin

  • 0
    TI__Guru** 120040 points

    Hi Kevin,

    We don't have this information.

    The exposed pad is required to connect to the pcb for thermal transfer, even if using the device in a socket. This device consumes a lot of current especially when all the output channel are used. It is pretty risky to leave the exposed pad unconnected. 

    FYI, the socket should have a bunch of teeth to connect the exposed pad to the pcb.

  • 0
    Prodigy 10 points

    Thanks Noel, that's good to know.

    I'm not sure if that socket in the picture you sent is known to specifically meant to accommodate the LMK04714-Q1, but if it is, would you mind sharing the make and model? I am currently looking to use the Yamaichi IC51-0644-807, but the datasheet, drawing, and 3D models had insufficient info on whether or not this IC would be a good mechanical fit with certainty. Otherwise, the info given suggests it would fit.

  • 0 in reply to Kevin Chen
    TI__Guru** 120040 points

    HI Kevin,

    Socket is usually tailor-made.

    You may check with Contech Solutions (https://www.contechsolutions.com/) or Ironwood Electronics (www.ironwoodelectronics.com). 

    We are using Ironwood CBT-QFE-3001 for other devices having the same package as LMK04714.