AD9851 SFDR vs Frequency at 180Mhz

Alfredo Mendiola Loyola

Dear All:

Is there a formula or method to calculate the worst SFDR at a particular frequency using a clock of 180 Mhz ?

I can't find that information on that datasheet, there is a chart about worst SFDR but at particular clock speeds and at 1/3 of that clock speeds.

I would like to know the worst SFDR for 20 0 30 Mhz using the 180 Mhz clock.


Alfredo Mendiola Loyola 

Lima, Peru



These spurious are more a result of the design than anything theoretical.  For your application, I would tend to use their 40.1 MHz example in the data sheet as representative of the maximum level spurs that you might see across a wide range.  It is close enough to predicted behavior since the levels change some between different parts. 


Alfredo Mendiola Loyola

Dear Curt:

Is -60dBC of SFDR a good number?

What is an acceptable SFDR spurs level that can we use with Antenna analyzers or Netowrk Analyzer?

Alfredo Mendiola Loyola


                 I don't think there is any standard for SFDR for any work. But the higher the better .Yes 60dB will be a good acceptable level for the antenna analyzer or network analyzer for normal ham use. Professional equipments demand more than 100dB SFDR and of course they are very costly for that reason.