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INA194: Low VSense operation

Mihir Gupta65
Intellectual 2155 points
Part Number: INA194
Other Parts Discussed in Thread: INA282, INA213

Hi Team,

I have a customer who is using the INA194 and had a question about the operation of the INA194 in the Low VSense mode as specified on page 19 of the datasheet.

In the case when VCM is 20V and VSense is <20mV, the INA194 is specified to have a maximum output voltage of 300mV. The questions are:

1. Is this value of 300mV specified over the entire temperature range? How would temperature affect this value?

2. How stable is a this specific offset Voltage over the lifetime? Can you specify the deviation of the value? Is it possible that this voltage would increase or decrease over the lifetime of the product?

Regards,

Mihir Gupta

FAE - South Germany

  • 0
    TI__Genius 14825 points

    Hello Mihir,


    The INA194 behavior is difficult to nail down with Vsense < 20mV.  To first answer your questions:

    1. 300mV is a typical number, not a maximum, per the electrical characteristics table.  Page 19 says that the number is a typical maximum, which is a little confusing, but basically we're trying to say that in general, the output at Vsense=0 is at or below 300mV.  The output could be above or below this number.  Also, this number is specified at 25C.  There is no spec over the full temperature range, which is specified in the adjacent column in the electrical characteristics table in the data sheet.  It is difficult to predict how this value will change with temperature.

    2. It is possible that this voltage will change with time.  We don't have data on the deviation.

    In our experience, it is difficult to calibrate out the performance of the device with Vsense < 20mV.  Depending on the common mode range needed, we have other products that typically satisfy design requirements if low offset measurements are needed.  The INA282 has very low offset and high common mode range, -14V to 80V with an up-to 18V supply.  If you only need up to 26V and don't go below 0V common mode, the INA213 is an excellent choice.


    If you would like to provide some design specifications, we can certainly help you find the part that is the best fit for your application.

  • 0 in reply to Jason Bridgmon
    TI__Intellectual 2155 points
    Hi Jason,

    Thanks for the reply. The customer's design is already in production, so changing it as this point would be a little difficult. Thanks for the suggestions for the alternate parts.

    Best Regards,
    Mihir