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INA2180-Q1: Common-Mode Transients Greater Than 28 V

Jade Lan
Intellectual 950 points
Part Number: INA2180-Q1
Other Parts Discussed in Thread: INA2290, INA2180, INA2181

Hi team,

Customer plans to use INA2180-Q1 on EMB and wants to know how to design to pass 35V@400ms load dump test.

Customer is considering designing based on the following circuit according to the datasheet. Are there any recommended Zener diodes? Or what parameter requirements should they meet? Or does team have any recommended circuits?

If the above circuit is selected, customer has the following problems.

  • If a 22V Zener diode is selected, there will be a voltage difference of 35V-22V=13V between the Zener diode and the power supply during load dump, resulting in a large power dissipation of the resistor. What value of resistor should be selected?
  • The maximum common-mode input of the INA2180-Q1 is 28V. How is this value determined? Is it permissible to exceed this value?
  • Are there any other multi-channel current-sense amplifiers with a common-mode voltage greater than 40V that you would recommend?

BR,

Jade Lan

  • 0
    TI__Expert 6225 points

    Hi Jade,

    -400ms is a long time. The circuit you showed is designed for short, transient pulses. If the pulse is short in duration then yes a 22V Zener diode is a good choice as long as the resistor you choose is rated to handle the amount of power being dumped into it. However, since this is a long pulse duration I would recommend using a device with a higher common-mode voltage rating. The INA2290 is a dual-channel device with a VCM range of 2.7V - 120V.

    -The common mode voltage of the device can be exceeded as long as the current going into the IN+ and IN- pins does not exceed 5mA. 

    The following image is from this AppNote: (It has information regarding different methods of handling electrical overstress).

     

    Best,

    Holly

  • 0 in reply to Holly R
    TI__Intellectual 950 points

    Hi Holly,

    Thank you for your suggestion.

    • Customer needs automotive devices, but INA2290 is not an automotive device. Are there any other products that meet their requirements?
    • If customer wants to use INA2180-Q1 to pass 35V@400ms load dump test, is it possible to use the circuit you recommended? What should be considered when selecting external components? 

    BR,

    Jade Lan

  • 0 in reply to Jade Lan
    TI__Expert 6225 points

    Hi Jade,

    Unfortunately our only automotive dual channels devices are the INA2180 and the INA2181 which have VCM maximum of 26V.

    Yes, the circuit I shared can be used. The AppNote I linked to previously gives detail about how to determine the ratings/values of the diodes and resistors.