L M X 2 5 3 1 L Q 2 8 2 0 E E V A L U A T I O N B O A R D O P E R A T I N G I N S T R U C T I O N S
PLL/VCO
The PLL/VCO tab shows all the important PLL controls. Reference Oscillator
should be programmed to the reference frequency connected to the OSCin of the
evaluation board. R Counter, Phase Detector Frequency, N Counter, and
Charge Pump Gain should be set to provide the desired output frequency with an
optimized loop filter. The desired VCO frequency may also be entered directly
into the VCO frequency box.
The LMX2531 also has an output divider which can be enabled by change divide
value from 1 to 2 by Fout frequency box. Be sure to load the device (Ctrl+L) after
changing this divider to allow the VCO to calibrate for optimal phase noise
performance.
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