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AD9954 and LVDS clock

Question asked by shabaz123 on Feb 28, 2011
Latest reply on Mar 1, 2011 by shabaz123

Hi,

 

I wanted to interface an LVDS oscillator (100MHz) to the AD9954, can I directly connect it to the

AD9954 REFCLK and *REFCLK inputs?

 

It wasn't clear from the datasheet if this was possible.

 

Here is the oscillator I'm planning to use:

http://www.farnell.com/datasheets/14202.pdf

 

Do I just need to connect the oscillator pins 4 and 5 to REFCLK and *REFCLK directly?

 

Should I use capacitors in series? Or will the AD9954 be happy with the LVDS source directly?

 

Secondly, the AD9954 data sheet says the REFCLK impedance is 1.5k, but the oscillator

requires a 100 ohm load, so will a 108 ohm resistor connected between REFCLK and *REFCLK

(so that the parallel impedance of 1.5k and 108 ohms equals 100 ohms) be ok?

 

Any hints/tips/schematics on using LVDS with the AD9954?

 

Thanks for your help.

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