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LM3886: V- Short to GND

Mitchell
Expert 4915 points
Part Number: LM3886

Hi Team,

My customer is seeing some strange behavior with LM3886TF/NOPB, which is the isolated package of the part. When the IC package body comes into contact with their chassis for heat sinking (grounded), V- shorts to GND. This is reproducible.  

We understand the body of the IC is at V-, but this is an isolated package, so we shouldn't need isolation between package body and chassis.

Can you let me know your feedback?

-Mitchell

  • 0
    TI__Mastermind 19840 points

    Hi Mitchell,

    The LM3886T package TA11B is a non-isolated package, setting the tab of the device and the heat sink at V − potential when the LM3886 is directly mounted to the heat sink using only thermal compound. If a mica washer is used in addition to thermal compound, θCS (case to sink) is increased, but the heat sink will be isolated from V − .

    Regards,

    Derek