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TL720M05-Q1: IC on Fire when output short to ground

Songzhen Guo
Intellectual 2840 points

Part Number: TL720M05-Q1

Hi expert,

In order to replace TLE42744DV50 on customer side, TL720M05-Q1 was tested on customer side. It's a powertrain application.

There are two test must be done:

1.Output short to ground;

2.Output short to battery(Max 40V);

When customer short the output to ground (VIn =6.5V), TL720M05-Q1 is on fire and it out of work.

Datasheet shows this device has overload and short-Circuit functions.

Could you check this for customer? Thanks.

Best Regards

Songzhen Guo

  • 0
    TI__Mastermind 23361 points

    Hi Songzhen, 

    The device has short-circuited protection, but when the short is applying on the output, please ensure the inductive spiking is not violating the absolute max of the output pin rating on the negative side, which is -1V. To help us identify the problem, will you help to provide more details on how the short-circuit test was conducted? 

    Thank you, 
    Jason Song

  • 0 in reply to Jason Song
    TI__Intellectual 2840 points

    Hi Jason,

    Thanks for your feedback.

    After check with customer, this application is a power train sensor, all the power is connected though wire connector.

    So for the short to ground test, Vin start from 6.5V, and it will increase to 40V.

    When Vin < 28V and short output to ground, it can work well;

    When Vin> 28V and short output to ground, it will on fire.

    Could you check it for us? and give us some suggestion? Thanks.

    Best Regards

    Songzhen Guo

  • 0 in reply to Songzhen Guo
    TI__Mastermind 23361 points

    Hi Songzhen, 

    Thanks for the update. With Vin> 28V, with the output shorting to ground, the peak current could go much higher than the current limit for a duration of a few microseconds. This delay is for the current limit loop to engage. It seems to me that with high than 28V, the package or the die of the IC cannot handle such peak current and unfortunately the IC will be damaged before the protection feature even kicks in. 

    That's over 30 watts through a tiny package which is just not feasible for the IC. We should probably advise the customer to only apply the short as pulses to control the duration for the short. Or to reduce the voltage for this short-test based on the reason I explained in the first paragraph. 

    Regards, 
    Jason Song