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Re: The difference of AD9523 and AD9523-1

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Hi Cien and Jonathan,

 

The AD9523 will be able to do this conversion and I believe most of your settings are correct.  One limitation in your frequency translation will be that the internal VCO in the AD9523 has a limited frequency range (3600MHz - 4000MHz) so your input multiplied by the feedback divider must be within this range.  Using 50MHz input, enable the doubler (located in PLL CTRL (F2)).  Next set the PLL2 N feedback divider to 40 (B counter set to 10  and A counter set to 0) to allow the VCO to lock to 4000MHz.  Then set the VCO divider to 4 and the OUT2 divider to 5 to give you the desired 200MHz clock frequency.

 

Next you will want to configure the loop filter for the output PLL as follows (located on page 7 of the document):

  • Pole2 Resistor = 225 ohms
  • Zero Resistor = 2.75k ohms
  • Pole 1 cap = 0pF
  • PLL2 charge pump = 896uA

These settings should give you a loop bandwidth of 430kHz and ~75 degrees of phase margin.  Please let me know if you have any questions.

 

Regards,

Kyle


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