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TPS548A28: Output current derating with temperature

JH Shin
Guru 11350 points
Part Number: TPS548A28


Tool/software:

Hello,

My customer has the following inquiry regarding the use of TPS548A28:

Q1. If you has any data to confirm output current derating for TPS548A28, please provide it.

Q2. They want to use TPS548A28 under the following conditions.

        - VIN = 12V, VOUT = 3.3V, IOUT = 9A(max)

      Is there any expected issue if the internal temperature of the system is high and the device temperature is used above 100 degrees Celsius (Not above 125 degrees Celsius)?

Thank you.

JH

  • 0
    TI__Genius 15187 points

    Hi JH, 

    Are you asking if TPS548A28 can be used under the condition of VIN = 12V, VOUT = 3.3V, IOUT = 9A(max) under ambient temperature of 100C? 

    WEBENCH is able to provide an estimate based on our EVM. 

    Power Designer

    • Enter Vin, Vout, Iout, Ta, Fsw,
    • Click export on top right
    • Scroll down to 'Charts' and click view more charts
      • Click IC TJ
    • The design will not allow for ambient temperature of 100C.

    This is at ambient temperature of 80C:

    This is at ambient temperature of 50C:

    Best,

    Ryan

  • 0 in reply to Ryan Chen
    Guru 11350 points

    Hi Ryan,

    Thank you for your reply.

    My customer's inquiry is based on the junction temperature of the device.

    Since the thermal analysis shows that the temperature of the TPS548A28 will exceed 100 degrees, they wanted to know the output current derating with temperature of the TPS548A28.

    The ambient temperature at this time is expected to be around 80 degrees Celsius.

    Is there any information on the output current derating with device temperature?

    Regards,

    JH

  • 0 in reply to JH Shin
    TI__Genius 15187 points

    Hi JH, 

    If the junction temperature is not exceeding the junction temperature of 125C, the output current will remain steady. However, this depends on the ambient temperature of the device. 

    Looking at ambient temperature of 80C, you can see the estimated Tj around 118C. The efficiency will decrease as the temperature increases, but the output current should remain the same. 

    Best,

    Ryan