Analog Devices AD9516 User Manual page 6

UG-075
6. Program the R (reference) divider by clicking the
R DIVIDER box at the top of the main window. Set
the desired value and click OK (see Figure 12).
7. Program the N (feedback) divider by clicking the
N DIVIDER box at top of the main window. Set the
desired value and click OK. For the example, N = 200
can use 8/9 dual modulus mode with A = 0 and B = 25.
8. Set the charge pump current by clicking the CHARGE
PUMP box in the upper right corner of the main window,
and then click OK.
9. Note that if the desired configuration has the phase
detector frequency above 50 MHz, an antibacklash pulse
width of 1.3 ns may work better. This setting is accessed by
clicking the PFD button to the left of the CHARGE PUMP
box. However, this setting normally does not need to be
modified.
10. Set the VCO divider by clicking the green VCO box in the
center of the main window, immediately to the left of the
Cal VCO button.
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Evaluation Board User Guide
11. Power down unused drivers, click the numbered triangular
symbol on the right side of the main window (see Figure 7),
select 2 - Safe Power Down, and click OK (see Figure 20).
Figure 7. Driver Symbol
12. Set the channel dividers by clicking DIVIDER 0 through
DIVIDER 4 and enter the divider ratio.
13. Click the flashing red WRITE button under the
REGISTER W/R section. This loads the desired settings
to the AD951x evaluation board,
14. Click the blinking yellow Cal VCO button to load the
VCO calibration window. The default VCO divide ratio
(16) works for all applications. Click the Cal VCO button
in the Calibrate VCO window to begin calibration (see
Figure 17). The PLL should now be locked and the LD
(lock detect) LED on the left side of the board should be on.