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Amplifiying 50KHz AC with Op Amps?

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eem2am

Aug 3, 2009
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Aug 3, 2009
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Hello,

I have a current sense resistor which has sinusoidal 50KHz AC current in it, as follows.....

http://i46.tinypic.com/xeqyl1.jpg


The voltage across the sense resistor is +/30mV.

The task is simply to amplify it to a voltage above 1.2V (1.2V is the trip level of the follow-on comparator).

.....The first opamp doesnt give much amplification due to the GBW.

However, i then add the RC filter, and a second amplfier which amplifies it to above 1.2V.

Do you know how i can work out the peak output voltage of the first (LHS) opamp?

Also, do you think this is the best way to do this?

.......basically, the sense resistor will either have current in it (50KHz AC) or zero current, and i simply have to flag that up.




LT1006 DATASHEET:
http://cds.linear.com/docs/Datasheet/1006fa.pdf
 
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