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Problem with AD9910/PCBZ

Question asked by abarry on Oct 18, 2010
Latest reply on Oct 18, 2010 by KennyG

We have been having some trouble getting started with the AD9910/PCBZ evaluation board.  We intend to use the 25 MHz crystal with the PLL to get a 1 GHz system clock.  We started out by removing C51 and C52, shorting R4 and R11, and setting the W7 jumper on XTAL.  The clock multiplier is off, since we have not modified the PLL filter yet.  I set the device to a 1 MHz single tone.  The filtered output of the PCB has a very fast oscillation, with a varying period on the order of 10-30 ns.  I checked the pins of the 25 MHz crystal, and there does not appear to be any signal.

 

Initially, we used the clock input connector (without the resistor and capcacitor changes), and injected a 50 MHz signal.  We had that working, but our clock source could not generate the 1 GHz signal we wanted to work with.

 

Is there anything that needs to be configured in the GUI to get the oscillator running?

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