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INA253: New CSA parts recommendations

user4811888
Intellectual 530 points
Part Number: INA253
Other Parts Discussed in Thread: INA181, INA180, INA301, INA290, INA280

Hi expert,

I post it under INA253 because I cannot find other new suitable parts.

My basic requirement can be described functionally as below, does TI have such INAxxx part number?

1. high bandwidth, typically over 250kHz current sensing capability

2. IMON function with current source output, up to 50A~100A current sensing capability. (easy to in parallel with current source)

3. input voltage range is typical 12Vin, no strict maximum value

4. Shunt resistor internal or external are both okay, package is at random

  • 0
    TI__Expert 4720 points

    Hello,

    I suggest an analog out with external shunt INA. The analog output relates a current on the input to a voltage on the output, using this output the current can be monitored. Having an external shunt allows you the freedom to be more flexible with devices and current ranges.

    Based on your bandwidth and typical 12 Vin.

    To satisfy your needs and a little extra I would suggest the INA180 (unidirectional) or INA181 (bidirectional) the gain option should be 20. So the INA180A1 or INA181A1. These have a bandwidth of 350kHz as well as a max common mode voltage of 26V. They provide an analog output so you are able to monitor the current. It will need an external shunt which can be calculated to suit your 50-100A current sensing capability. If you would like a more precise current measurement with same features I suggest the INA185A1.

    Going above your requirements with more bandwidth and more common mode range there is the INA301. The bandwidth is up to 550kHz as well as 36V common mode max. It also has an alert feature that can be programed to trip based on a current. The analog output can be monitored for current and/or the alert pin can be monitored for a certain current trip condition.

    Going well above your requirements we have the INA280 and INA290 which far exceed the limits, but are ultra precise current sense amplifiers. 

    If you have any questions please reply

    Regards,

    Castrense

  • 0 in reply to Castrense Nigrelli
    Intellectual 530 points

    Thanks very much for your so clear and detailed recommendations.

    If I use INA180A1 and Vs=3.3V, when input current is 100A flowing through shunt resistor=1mOhm, the maximum input voltage is 100m, and maximum output is 2V, is it right?

  • 0 in reply to user4811888
    TI__Expert 4720 points

    Hello,

    Yes and no, in theory yes it will be 2V but because the INA180 has measurement errors this will not be the case. When measuring high currents the biggest contributing factor to the error will be gain error. If you take the max gain error of 1% the output becomes at worst 1.98V or 2.02V. Note there are other errors, but will play a lesser effect in this situation.

    There are other considerations to take into account. The biggest problem I see is the power tolerance of the resistor you have chosen with the current you are trying to measure. 

    P = I^2 * Rshunt = 100^2 * 1mOhm = 10 W. Be sure to pick a resistor that will tolerate this condition. 

    If you have any questions please reply

    Regards,

    Castrense