• State
  • Locked Locked
  • Replies 2 replies
  • Subscribers 49 subscribers
  • Views 419 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.

Capacitance input (C cm) of THS3001

Currobosch
Prodigy 20 points
Other Parts Discussed in Thread: THS3001, THS3092

Hello people,

I would like to know the Noninverting input capacitance (Ccm, common mode) of Op Amp THS3001. Thanks.

I want to put a series resistance at the noninverting input, because of limiting current, if overvoltage is reached, therefore I need to know it for calculate the max resistance.

Thsnks!

  • 0
    TI__Genius 12631 points

    Hello,

     Unfortunately it looks like the input capacitance was not measured/simulated at the time of release. This is quite an old part so it is going to be difficult getting into the database to check this. A good rule of thumb is C_cm = 1/2 of Cdiff, so around 4pF in this case. I should mention that making the input impedance very large will also cause an output offset due to Ibias x R effect. For a typical Ibias = 2uA, the output offset with a 1KOhm resistor will be 2mV...for the max Ibias = 10uA @ 25C, this will result in 10mV of offset.

    -Samir

  • 0 in reply to Samir Cherian
    Prodigy 20 points

    Thanks Samir!!

    But in the most devices, that I seen, Cdiff < C_cm. Anyway I chose other Op. amp. THS3092, that is cheaper and better specified datasheet...

    Best regards,

    Francisco