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Using AD8055 as a non-inverting op-amp

Question asked by werty on Mar 3, 2011
Latest reply on Mar 7, 2011 by JohnA

Hi there!

 

I am using an AD8055 in a circuit. The IC is currently being used as an non-inverting op-amp as in figure 38, page 12, of  the AD8055 's datasheet. The input is from a tuned circuit (inductor and  capacitor in parallel) and is at 200kHz with the peak to peak voltage being  about 40mV. However, whenever the tuned circuit is connected to the op-amp, the  output of the op-amp quickly "saturates" (and oscillates between +/- 3V) with an  input voltage of only 40mV and a gain less than 10. Strangely enough, this  oscillation does not occur at low gains (about +3). However, I require the  op-amp to have a gain of about 100 eventually.

 

Could someone help me sort out this problem please?

 

Thanks for the help!

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