0 Replies Latest reply on Dec 26, 2017 2:35 PM by user_301665782

    Ac coupled Non_Inverted amplifier with op amp  1.90

    user_301665782

      Hi there, Happy Holidays.

       

      I would need some help with attached project  because I am not analog designer.

       

      The point is that I cannot get a aproximately flat range of frequencies  required with a flat gain.

       

      I need a aproximately flat response from 500 Hz to 10,000 Hz .may be there are other solution I do not Know .

       

      The facts are these:

       

      The Gain is set to 4.3 or 12.7 db

       

      Vin is 55 mv p-p. sinusoide and keeps constant.

       

      Under 500 hz the behavior is the espected, I mean the gain increase as frecuency increase.

       

      Over 500 or 600 Hz the gain reach the espected 12,7db but it does increase as frecuency increase to big 

       

      values, I mean  much more than 12.7 db .

       

      Near ,6000 or 7,000 hz there is a marked distortion.

       

      Above  aprox 7000 Hz the gain keeps incresing and also the distortion.

       

      Based on : GBW = 3 MHZ and G = 4.3  the espected BW should be around +/- 20% of 698 KHZ. but that is not obtained.

       

       

      The following table list readings from Rigol DS1102D scope  using the whole sreen amplitud for reading volt values.

       

      Hz          mv P-P

       

      300          36  

       

      1000         96

       

      3000         275

       

      6000         622

       

      6500         1320

       

      Above these frequencies the waveform is totally distorted and  the V p-p increase up to the rail.

      Thank you very much for any Help.