(AD8207) Is the input bias current is matched?

Hi !

I have a question about AD8207.

At AD8418A, input bias current is mismatched.

But AD8207 it looks bias current is matched.

Is my understanding correct?

Best regards.

Kawa

  • 0
    •  Analog Employees 
    on Nov 7, 2016 4:18 PM

    Hi Kawa, 

    I will confirm that and get back to you.

    Thanks, 

    Kris

  • Hi Kris.

    Thank you for your support & reply.

    I will add my question.

    Q1)

    Is AD8207 input current is mismatched or matched?

    Q2)

    If it is matched can you tell tell variations of the AD8207 input current?

    Q3)

    Can you show the graph with more wide range for common mode voltage?

    => Our customer want to know what will happen when the swing the common level to survival level.

          So they want to know Bias current VS Common-Mode voltage for this range

          * AD8418A   -4 to 85V

          * AD8207      -25 to 75V

    Q4)

    Can you show the graph with more wide range for CMRR?

    Our customer want to know DC to 10MHz .

    Best regards.

    Kawa

  • 0
    •  Analog Employees 
    on Nov 9, 2016 8:56 AM

    Hi Kawa,

    I have confirmed that the bias currents on the AD8207 are matched. 

    Could you expound on why you need information up to the absolute maximum ratings? What is the customer's application and is operation in their case expected to go down to those ranges?

    Thanks, 

    Kris

  • Hi kirf

    Thank you for you support every day.

    Our customer were using AD8418A for sensing motor phase.

    But at their application , common voltage drops too much and it was over the absolute maximum.

    They tried to fix that problem but it was very difficult to do that.

    So for the second opinion, they are thinking to change AD8418A to AD8207.

    Q2)

    => they want to know this because they want to calculate the error when they input some filter in front of AD8207.

    Q3)

    => at their application, as I said they are measuring motor phase current,

         The common level will drop maybe more than -10V.

         They want to know what will happen to the input side when this happen.

          So they want to see the graph with more wide range for common mode voltage.

    Q4)

    => With their application , fastest CMMR will be 8MHz.

          So they want to know CMRR graph to 10MHz.

          Both AD8207 and AD8418A.

    Best regards.

    Kawa 

  • Hi krisf

    Thank you for your reply and your support everyday!

    If you want to know more information about this project, please feel free to ask me.

    Best regards.

    Kawa