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DRV8432 Maximum shutdown Temperatur

Sebastian Graf
Prodigy 90 points

HI,

we are using a DRV8432 in parallel mode. While driving in extrem condition (45°C ambient temperature, maximum current) the cooling system is working on top . Most of our devices work successful (with an over temperature warning) in that condition, but some are switching off caused by over temperature shutdown of the DRV8432.

We expect the shutdown at 150°C chip temperature. [Datasheet: max., operationg junction temperature 150°C]

Our test results out of our device show:

Good devices had a IC which shutdown in a test (out of device) at about 148°C.

Bad devices had a IC which shutdown at 134°C or 141°C.

Is there such a big spreading with the shutdown temperature? Can someone give me a trustable value on which the chip will not go in over temperature shutdown?

Thanks for your help

  • 0
    TI__Expert 4650 points
    Hi Sebastian,

    How are you measuring this shutdown temperature? The driver will enter thermal shutdown when the junction temperature is 150°C, not the case temperature.

    Our recommended measurement method to estimate the junction temperature is outlined in this thermal application note below:

    www.ti.com/.../sluu484.pdf
  • 0 in reply to Phil Beard
    Prodigy 90 points
    Hi Phil,

    thank fou for your quick answer. We are measuring the case temperature via thermal IR camera. for verifying good measurement we do many repetitions. We are heating the system through the chip, so we do have similar chip Power each time. Therefore I would expect similar shutdown temp. values at different devices.

    Best regards
    Sebastian