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UG-002 Evaluation Board User Guide
Rev. 0 | Page 12 of 12
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Figure 25. Register Debug Window
Figure 26. Input PLL + DCXO Window
11. Bit 3 of Register 0x17 must be set to 1 to enable the PLL
locked pin as a test port. By default, the 26 MHz crystal
frequency is present at the output.
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12. The ac signal has a dc offset of approximately 1.6 V. Be
aware that some test equipment has a limit of 0 V dc;
therefore, a dc block must be used in such cases.
SETTING THE 19.44 MHz MODE
The following instructions can be used to configure the
AD9551 to operate in the 19.44 MHz mode. Refer to the
AD9551 data sheet for more details about this mode of
operation.
The following case is an example for the AD9551 in
19.44 MHz mode:
Figure 27. PFD and Charge Pump Window
6. Change the charge pump current to the appropriate
current level specified in the AD9551 data sheet
(approximately 25 µA), and then click OK.
1. Replace the crystal on the evaluation board.
2. Replace the loop filter capacitor on the evaluation board.
3. Click Click for Details in the PLL & DCXO box in the
main window of the evaluation board software to access
the Input PLL + DCXO window (see Figure 26).
7. If the LOAD button in the main window starts blinking,
this indicates that there are settings that have not been
loaded to the AD9551 evaluation board. Click LOAD to
load these settings to the evaluation board.
4. Select 19.44MHz Mode in the Input PLL Mode: box, and
then click OK.
ESD CAUTION
5. Click Click for Details in the PFD & Charge Pump box in
the main window of the evaluation board software to
access the PFD and Charge Pump window (see Figure 27).
Evaluation boards are only intended for device evaluation and not for production purposes. Evaluation boards are supplied “as is” and without warranties of any kind, express,
implied, or statutory including, but not limited to, any implied warranty of merchantability or fitness for a particular purpose. No license is granted by implication or otherwise under
any patents or other intellectual property by application or use of evaluation boards. Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Analog Devices reserves the
right to change devices or specifications at any time without notice. Trademarks and registered trademarks are the property of their respective owners. Evaluation boards are not
authorized to be used in life support devices or systems.
©2009 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
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