• State
  • Locked Locked
  • Replies 2 replies
  • Subscribers 47 subscribers
  • Views 3002 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Any drawback tying all gaurds pins toghether on an INA116 Instrumentation Amp?

Edward Dempsey
Prodigy 10 points
Other Parts Discussed in Thread: INA116

Hi,

We are in the process of utilizing the INA116 in a current PCB design and had a question regarding the connection of the guard pins on the INA116. The engineer that did the board layout ended up tying all guard pins together for simplicity in the board design. I have looked at the INA116 data-sheet and have noticed they always show pins 2 & 4 tied together and used as a shield for the Vin- pin3. In addition pins 5 & 7 are shown connected and used to shield pin 6 or Vin+. In our design we surrounded both Vin - & + but connected pins 4 & 5 together which ends up placing these two guards  at the same potential. Would this cause any detrimental affects to circuit operation, ex: increased noise?

 

Any help would be greatly appreciated!

 

Regards,

 

Ed

  • 0
    Guru 21975 points

    Ed,

    The connection you describe defeats the purpose of the guard pins. The voltage on these pins is derived from and equal to the input voltage on its associated input terminal. Connecting them all together will cause the guards to be at the wrong voltage for both inputs.  I do not recommend this connection.

    Regards, Bruce.

  • 0 in reply to Bruce Trump
    Prodigy 50 points

    Hi Bruce,

    I'm new to this forum and could not open the guarding diagram that you posted. Is there any other way of guarding apart from using coaxial cables.

     

    Regards

     

    Caglar