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LM337-N-MIL: LM337H/NOPB; suspected failure due to touching the lid body

Amira Roslan
Prodigy 70 points
Part Number: LM337-N-MIL

In our Amplifier application, the Voltage regulator of LM337H/NOPB is touching the metal lid of the body casing, it then causes the failure: short circuit between this voltage regulator LM337H/NOPB and the lid body casing. It results in a voltage drop for the unit. The working voltage for the unit was 15V. The voltage drops to around 6V. 

We need advice, is it the metal body of the voltage regulator LM337H/NOPB that may cause the short circuit if it touches with other components/metal components? Because, from our understanding, the body of the component should be inductive, and not conductive. 

LM337H/NOPB touching the lid body casing

  • 0
    TI__Genius 12511 points

    Hi Amira,

    I'm unable to find the MB diagram for the LM337H/NOPB, but looking at the LM337LMX/NOPB  to see the connections made, the case is GND of the device. By changing the potential of the GND of the device, you may see operational differences. This could result in a drop or increase in output voltage depending upon how the GND plan e had been moved.

    Regards,

    John

  • 0 in reply to John Schneider
    Prodigy 70 points

    Hi John, thank you for the reply. 

    But when the metal body of the voltage regulator LM337H/NOPB (as image below) touches with other metal components, can it cause short circuit?

        

  • +1 in reply to Amira Roslan
    TI__Genius 12511 points

    Hi Amria,

    Since there is a connection from the body to the GND, there is not a VOUT short to GND, but yes by shorting any plane you can cause a problem. In this case a GND short would cause a shift in the plane and possible increases in current when the short occurs.

    Regards,

    John