AD9910EVB_Filter Question

Document created by analog-archivist Employee on Feb 23, 2016
Version 1Show Document
  • View in full screen mode

I have a query about the AD9910EVB. I found that the component values of the
output 400MHz filter on this board is not same as his simulation values. What
they considered is a 0.001dB inband error with a 50 Ohm impedance filter. The
numbers they calculated are as follows:
   L1=L3=24.69666935nH
   L2=30.77539346nH
   C1=C4=4.689341243pF
   C2=C3=12.18975667pF
However, the values on our EVB are:
   L1=L3=24nH
   L2=30nH
   C1=C4=6.6pF
   C2=C3=12.8pF
So, we are wondering why there exists some difference between them. Is there
some other consideration.
Would you mind sharing your experience on this question.

 

Most times we use 0.01dB for pass band ripple, not 0.001db. Also we round the
capacitors values to the closest value we have in stock.
Those two things are probably the difference.

Attachments

    Outcomes