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INA240-Q1: INA240A3QDRQ1

Raja Sekhar
Prodigy 10 points
Part Number: INA240-Q1

Tool/software:

Dear TI Support Team,

I am experiencing failures with the INA240A3QDRQ1 current sense amplifier under specific conditions. Below are the details:

Test Conditions:

  1. Input Voltage: 5V applied across input pins 6 and 7 of the INA240A3QDRQ1 with respect to GND (pins 2, 3, and 4).
  2. Test Setup: As per the attached schematic.

             

Issue Observed:

  • Initially, the device generates a 2.5V reference voltage, and at times, it functions correctly, with the reference voltage varying based on the load in both directions.
  • After some time, the reference voltage at pin 5 shifts to either 0.5V or 5V (both conditions have been observed).
  • When a load is applied, even as low as 1A, the IC fails.
  • The IC also fails when varying the duty cycle of the input voltage.
  • These issues have been confirmed through oscilloscope observations.

Could you please assist in identifying potential causes for these failures? Additionally, any recommendations for improving circuit reliability or failure analysis would be greatly appreciated.

Looking forward to your support

  • 0
    TI__Mastermind 30450 points

    Hello Raja,

    I do not see any issues with your schematic.  Could you please share the scope shots and the expected output.

    Raja Sekhar said:
    Initially, the device generates a 2.5V reference voltage, and at times, it functions correctly, with the reference voltage varying based on the load in both directions.

    I don't want to confuse the naming but I normally consider this Vout, and not the reference.  When I state reference I assume you mean the Vout when the input is zero.

    Raja Sekhar said:
    After some time, the reference voltage at pin 5 shifts to either 0.5V or 5V (both conditions have been observed).

    Is this output with Zero input?  Can you share the input voltage during these conditions.

    Raja Sekhar said:
    The IC also fails when varying the duty cycle of the input voltage.

    Can you share the VCM (Voltage common mode) or scope shot of this and the expected behavior.

    Regards,

    Javier

  • 0
    Prodigy 10 points

    Hello javier,

    INA output is keep on failing.At the time of failing it is trying to varying b/w 4V and 0.5 V.

    Let me know what to do ,we keep on replacing ic's

    ( Since it is a automotive product it is not good)

  • 0 in reply to Javier Contreras4
    Prodigy 10 points

    Reg ,After some time, the reference voltage at pin 5 shifts to either 0.5V or 5V (both conditions have been observed).

    Input voltage is always 5V but output at pin 5 is 0.5 or 5V it is showing and my expected output is 2.5V

  • 0 in reply to Raja Sekhar
    TI__Mastermind 30450 points

    Hello Raja,

    Can you please share scope shot of your test points(TP207, TP208, TP209) with respect to TP210.  The schematic portion you shared looks fine and I would not expect any of this.  What Rshunt are you using?

    Also please look at my questions above.

    Regards,

    Jaiver

  • 0 in reply to Javier Contreras4
    Prodigy 10 points

    Hello Javier,

    Thank you for your quick reply.

    Currently, I am out of town. Once I reach the workstation, I will share the information with you immediately. In the meantime, if possible, could you share any reference circuits related to the INA240A3, specifically for high-current charge and discharge applications?

  • 0 in reply to Raja Sekhar
    TI__Mastermind 30450 points

    Hello Raja,

    I do not have anything just making sure the pins do not go over absolute maximum ratings.  If we narrow down the issue I may have things to mitigate it.

    Regards,

    Javier