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9912/9913 getting started

Question asked by DanCA on Jul 26, 2011
Latest reply on Jul 26, 2011 by DanCA



I will be using either a 9912 or 9913 eval board pretty much as is for a low-phase noise synthesizer...and I am a bit confused about the acceptable input/output impedances and other basic isssues. I should note that I am a physical chemist, not an EE expert yet! I had a few specific questions, below. Any help would be greatly appreciated!


0) Revision numbers? There is a 9912 eval board A and then an eval board B as well; I want a 'B' as it was modified to have a pull-down resistor in place for PLL bypass (for better phase noise). What revision of eval board is A/D currently selling? It is unclear to me if it is eval board A or B.


1) My REF CLK will be a single-ended sinusoidal signal supplied from a 50 Ohm RF amplifier (either at ~80MHz or ~1GHz for 9912,9913 respectively). Is this OK to input to the eval board as is, or do I need to some sort of impedance matching on the REF CLK input?


2) For the output, I'll use the hopefully sinusoidal, filtered output; this signal will be fed into additional RF components (mixer, bandpass, amp,etc.) meant for 50 Ohm impedance. Given that I'll use the 'reconstruction filter' already included on the eval board, can I use the output as is, or do I need to change the eval board's output impedance, coupling,etc. ?


3) 'Construction issues': It is my understanding that I should put the eval board in a metal chassis to avoid EMI issues. So in that regard:

are there any practical things to be aware of, e.g. should I concern myself with the potential for gound loops if I don't use insulated box-wall feedthrough connectors for some of the REF_CLK and output signals,etc.?


Thanks in advance for any help!