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DRV8801A-Q1: Overmold on QFN package

Jared Becker
Genius 11845 points
Part Number: DRV8801A-Q1

Hi Team,

In reading up on packing failure modes with overmolding, I’ve just learned that QFN packages are higher risk packages.  The DRV8801A-Q1 is in a QFN package.  In production, the device will be covered with a mold material, CTE ranging from 150 to 300 ppm/deg C temperature cycling.

I’m looking for any data or caution from you guys regard this package type and its use with our overmold material.

Looking forward to your feedback.

-Jared

  • 0
    TI__Expert 8985 points

    Hi Jared,


    When you mention packing failure modes, do you mean QFN packaged ICs have a high risk of failing different kinds of packing techniques due to the overmold material?
     
     
    We will look into any available data/cautions we might have with overmold material within our resources.

  • 0 in reply to Hector Hernandez Luque
    TI__Genius 11845 points
    Hi Hector,

    I mean to say that when QFN packages are put through a stressful, heated environment, they can be prone to failures. When this overmold is applied to the PCB, the overmold also covers the QFN package and is put through heating cycles. I just want to understand the risks associated with doing this.

    Best,
    Jared
  • 0 in reply to Jared Becker
    TI__Expert 8985 points
    Hi Jared,

    I understand your question as it being related to how over mold material reacts when being applied above a QFN package and it being put through heating cycles with the CTE value range specified. From what I gathered, QFN packages by themselves come with a quality design benefit to reduce stress caused by an automotive environment: wettable flanks, which assist in creating a better conductive path to the PCB traces from the QFN package. Also, having a clean PCB layout, along with no residue solder, allows for dendritic growth to have a lesser probability of occurring.

    As for the over mold material, let's take potting compound as an example. A slow cure potting compound helps with the removal of heat, yet stress comes with utilizing such material. For more information on effects of over mold material on QFN packages, I suggest contacting an over mold material manufacturer and see the data they might have as related to its effects on QFN packages in general.

    The wettable flank are found on the physical diagrams page of the DRV8801A-Q1, found on page 22 of its datasheet. See URL below:

    www.ti.com/.../drv8801a-q1.pdf