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ADG936 for switching output AD995x?

I search switch for switching current output from DDS AD995x I look AD936 but I have problem understand DC bias.

Is possible use AD936 in substitution for relay on this design?

http://www.flickr.com/photos/82976793@N08/7596371626/in/photostream

  • Hello wivern,

    Thank you for your enquiry.  From your schematic it looks like you have a +1.8V bias going through the relay.  The ADG936 is an NMOS switch, the relationship of Vsource to Ron is plotted below.  Therefore a 1.8V bias will yield a very high Ron (switch turns off).  So I think the ADG9xx switches are not a good fit here. 

    That said, can you tell me the max frequency of the signal you will use and the highest voltage supply you can use.  There maybe another switch in our catalogue that could be suitable.   

  • OK, if you need up to 2GHz then the ADG9xx series is all we currently have with that kind of bandwidth.  Looking at the schematic again.  Would it be possible for you to move the DC bias feeds and 1uF DC blocking caps to the left side of the switch rather than the right.  If this is an option then ADG936 could work.

  • Thanks for information. Unfortunately, to go about teaching and experimental devices using harmonic  products of  DDS. Therefore, the switch must go up to 1.5GHz (better 2GHz).

    Find a switch for the frequency range DC-1, 5GHz is apparently a problem.