Source <1|2>; Referencedoubler <Enable|Disable; Source <1|2>; Referencedivider <Enable|Disable; Source <1|2>; Chargepump <0|1|2 - Valon 5009a Operation Manual

Reference
Doubler
Reference
x1
Frequncy in
x2
In
The Reference Doubler and Reference Divider can be user set to optimize the PFD frequency to
40MHz when an external reference is applied. For example, if an external reference of 10MHz is
applied, the user should set the Reference Doubler to2 using the DEFDB command.
Setting the PFD frequency then allows the 5009 to determine the closest R-Divider value that
will provide the selected PFD frequency based on the previously set Reference Frequency,
Reference Doubler setting, and Reference Divider setting. Selected PFD frequencies should be
low-valued multiples of the actual reference frequency.
Sending the "PFD?" command will return the actual PFD frequency.
Example: PFD set to 40MHz with the External Reference of 100MHz, Reference Doubler
disabled(x1), and reference divider disabled (1/1). The 5009 would select an R-Divider value of 3
(providing the closest PFD in the 20MHz to 50MHz range). Sending a "PFD?" command would
return PFD=33.333333MHz.
Example 2: PFD set to 25MHz with the Internal Reference of 40MHz, Reference Doubler
enabled(x2), and reference divider disabled (1/1). The 5009 would select an R-Divider value of
3. Sending a "PFD?" command would return PFD=26.666667MHz.
Example 3: PFD set to 22MHz with the Internal Reference of 40MHz, Reference Doubler
disabled(x1), and reference divider disabled(1/1). The 5009 would select an R-Divider value of 2.
Sending a "PFD?" command would return PFD=20.000000MHz.
Source <1|2>; REFerenceDouBler <Enable|Disable>
4.10.5
REFDB enables or disables reference doubler. The referenced doubler multiplies the internal or
external reference frequency by 2. With the internal 20MHz reference, the reference doubler is
defaulted to off. Enable the reference doubler when the external reference is less than 20MHz.
The reference doubler function precedes the PLL R divider function. The reference doubler
should not be enabled when the reference divider is enabled. {r2, b25}
Source <1|2>; REFerenceDIVider <Enable|Disable>
4.10.6
or REFDIV enable or disable reference divider. The referenced divider divides the internal or
external reference frequency by 2. With the internal 40MHz reference the reference divider is
defaulted to off. The Reference Divider is not normally used and actual use is tbd. {r2, b24}.
Source <1|2>; ChargePump <0|1|2|...15>
4.10.7
CP Sets the 4-bit charge pump current. Optimum value is 7 but users can optimize this setting to
optimize minimize phase noise at a particular frequency.
Valon Technology 5009a Operations Manual – Version 1.38
Reference
R-Divider Divider
x1
R=1:1023
x0.5
Phase/Frequency
Detector
PLL Loop
Filter
Feedback
from N-Divider
Page 32