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ADCLK944, ADL5385 & AD8347

Question asked by DaveS- on May 24, 2012
Latest reply on May 28, 2012 by THA

Hi

I have a design which uses a ADCLK944 to provide fanout for local oscillator to two AD8347's and two AD5385's in the frequency range 900-2200MHz and all powered at 3.3V. All of the components are on one PCB and maximum track length is around 60mm from each device to the ADCLK944.

I want to use a 2 layer PCB and I am looking for the best way to route and terminate each circuit.

My intention is to use two 50ohm tracks (+ & -) from the ADCLK944 directly to each input differential pair.

I note that the ADL5385 has 50ohm impedance inputs, would I need to use (100n) DC blocking capacitors?

The AD8347 I would use 100pF series capacitors in each track and a 200ohm shunt resistor all at the AD8347 end of the track.

 

Any comments appreciated.

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