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INA301: LIMIT pin current in Ta 65C and programmable Rlimit

user4979989
Intellectual 2800 points
Part Number: INA301

Hi team,

1. My customer wants to know LIMIT pin tolerance spec at Ta=65 degree, do we have this data for this specific temperature? 

2. Can we implement the digital potentiometer(variable resistance) in LIMIT pin to achieve programmable current limit function? (I know DAC can be the solution)

Thank you!

  • 0
    TI__Mastermind 26335 points

    Hello user4979989,

    Thanks for reaching out on our forum.

    1. We unfortunately do not have measurements specifically at 65C.  However, I can provide you the range over the interpolated values we have at 65C.  Over a sample set greater than 10, the Limit current ranges from 79.8uA to 80.17uA.

    2. Yes you can implement a digital potentiometer for a variable alert trigger point.  However, just be aware that a digital potentiometer has a terminal leakage current (example below) that can result in the limit voltage to deviate from the ideal expected value.

  • 0 in reply to Patrick Simmons
    TI__Intellectual 2800 points
    Hi Simmons,

    Thanks for replying, one more question for LIMIT pin, what will happen if LIMIT pin is open or shorted to ground?
    Will it have a default current threshold?
  • 0 in reply to user4979989
    TI__Mastermind 26335 points

    Hello user4979989,

    If you short the LIMIT pin to ground your ALERT pin will go low and stay low with the internal current source still outputting the default current amount. I presume you are trying to lower your current and power consumption. If that is the case, I would pull the LIMIT pin up to VCC with a 10k. However, I cannot readily tell you how much that would reduce the overall quiescent current.

  • 0 in reply to Patrick Simmons
    TI__Intellectual 2800 points
    Hi Simmons,

    Thank you, customer raised two more question about ILIMIT pin current tolerance.
    1. If ILIMIT piu current tolerance is 79.8uA~80.17uA, can I say the typical value is 79.985uA in 65 degreeC?
    2. How about ILIMIT pin current tolerance in Ta between 10 degreeC to 65 degreeC?
    3. How about ILIMIT pin current tolerance in Ta 10 degreeC?

    Thank you
  • 0 in reply to user4979989
    TI__Mastermind 26335 points
    Hello user 4979989,
    1. The average of the interpolated values is 80.01398uA.
    2. The change between the min and max over that temperature range for the samples we have is 0.344uA. However, a larger sample set may yield a wider distribution, which the datasheet accounts for.
    3. The difference between the min and max interpolated measurement is 0.48uA. Yet again, more samples will produce a larger distribution. However, these will fall within the datasheet specification.
  • 0 in reply to Patrick Simmons
    Prodigy 10 points

    Hi

    Could you let me know the max value and min value between 10 degreeC to 65 degreeC? because we want to know accuracy on INA301

  • 0 in reply to Po Yi Li
    TI__Mastermind 26335 points
    Hello Po Yi Li,

    The minimum and maximum of the interpolated points is 79.85667uA and 80.17433uA, while the minimum and maximum of nearest measured temperature is 79.845uA and 80.17433uA.