L M K 0 4 9 0 6 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
SNAU126
27
PLL2 N Total = VCO Divider * PLL2 N Prescaler * PLL2 N Counter
Clicking on the cyan-colored PLL2 block that contains R, PDF and N values will bring the
PLL2
tab into focus where these values may be modified, if needed.
Clicking on the values in the box containing the Internal Loop Filter component (R3, C3, R4,
C4) allow one to step through the possible values. Left click to increase the component value,
and right click to decrease the value. These values can also be changed in the
Bits/Pins
tab.
The Reference Oscillator value field may be changed in either the
Clock Outputs
tab or the
PLL2
tab. The PLL2 Reference frequency should match the frequency of the onboard VCXO or
Crystal (i.e. VCO frequency in the
PLL1
tab); if not, a warning message will appear to indicate
that the PLL(s) may be out of lock, as highlighted by the red box in Figure 10.
Figure 10: Warning message indicating mismatch between
PLL1 VCO frequency (30.72MHz) and PLL2 reference frequency (122.88 MHz)