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AD8429 gain peaking at high frequency

Question asked by Michele61 on Feb 1, 2016
Latest reply on Feb 1, 2016 by harryh

I am trying to use AD8429 to amplify signals at frequency up to 5-10 MHz.

I am testing a basic scheme on breadboard (with gain 7):AD8429_test_small.jpg

 

and I find a large peaking in gain at about 7 MHz. I repeated measurements with different values of the gain resistor R3, and also without the RFI input network.

gain.PNG

phase.PNG

 

These results are quite different from the Gain vs. Frequency figure reported in the datasheet (Figure 9 page 8).

By the use of a small (5 pF) capacitor across the gain resistor R3 I can slightly improve the situation.

Do you think that it is possible to stabilize these amps on breadboard? Is there any suggested stabilization scheme?

 

Thanks in advance

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