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INA201: INA201 output accuracy

Roger Ding
Intellectual 1720 points
Part Number: INA201
Other Parts Discussed in Thread: INA301

Hi,

there is question of INA201 output accuracy with my customer.

INA201 amplifier out pin will be up to 1V in case 2. It means when they design the OCP function, the amplifier out pin must be setting higher than 1V for the OCP point, is that right?

They hope to get the distribution data of this characteristics.

  • 0
    Guru 140200 points

    Hi Roger,

    the threshold of comparator of INA201 is 0.6V, as shown in figure 1 of datasheet. See also section 6.6 of datasheet.

    Kai

  • 0
    TI__Genius 17100 points

    Hi Roger,

    The INA201 has varying accuracy based on Vsense, Vcm, and Vs voltage levels, especially as Vcm decreases below Vs as shown in the datasheet excerpt below:



    Depending on which case 2 you have (Normal or Low Vsense) the amplifier output pin can be drastically inaccurate. What are your Vcm, Rs, and Vs values?

    The comparator will respond when the input to CMPin > 0.6V. If a system requires the comparator to trip at a different voltage, a resistor divider network can be used to scale the voltage down on the output pin. For example, on the datasheet capture below the comparator will trip if Vout = 1.1V, R3 = 4kΩ and R4 = 6kΩ.

    Also, depending on the package a pin-to-pin compatible device with the INA201 is the INA301 which features a lower common mode voltage range. The customer may consider this part.


    I will await your response,
    Manuel Chavez

  • 0 in reply to Manuel Chavez
    TI__Intellectual 1720 points

    INA201 output accuracy.docxHi Chavez

    please see my attached document, there is attached questions.

    Roger Ding

  • 0 in reply to Roger Ding
    Guru 140200 points
    Hi Roger,

    have you had a look at section 9.1 "Output vs Supply Ramp Considerations" ? From figure 37, I think, it cannot be exluded that the comparator triggers during power on.

    Kai
  • 0 in reply to Roger Ding
    TI__Genius 17100 points
    Hi Roger and Kai,

    For the low Vsense case 2, output of the amplifier is unpredictable. For normal operation – once your Vs ramps and Vcm is on – it seems like you are operating in Low Vsense Case 3 (Vsense = ~15mV, Isense = ~1.5A).

    To answer your question: yes, the output pin will potentially rise to 1.5V as the supply ramps, triggering the OCP comparator. This initial spike can be ignored by incorporating an initial period of ~5mS where trips are ignored in the software.

    I hope this is helpful, please respond if details are necessary.

    Best,
    Manuel Chavez