Texas Instruments CDCE62005, Руководство пользователя, Страница: 6 / 18

Installing the EVM Control Software and USB Driver
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The PFD and Charge Pump section of the EVMCS can be clicked for a popup window that opens, as
shown in
Figure 5 , showing selections for the charge pump current and charge pump pulse width. For the
internal loop filter, lower charge pump currents work well and for the external loop filter, higher charge
pump currents work well.
Figure 5. Charge Pump
4. Loop Filter Selection
The Loop Filter section of the EVMCS can be clicked for a popup window that shows the internal
loop-filter configuration, where the values of the resistors and capacitors of the active loop filter can be
selected from the allowable dropdown list for each component.
Figure 6. Loop Filter, Internal Only
Alternately, the loop filter with additional external components can be enabled by clicking the “Use
External Loop Filter Components” button and by enabling the appropriate DIPswitches (SW9 and
SW10) on the bottom of the CDCE62005EVM as described in the “Configuring the Board” section of
this User’s Guide. The external loop filter components (C4, R4 and C5) are in green in the picture
displayed below. The component values entered into the text boxes are saved when a configuration
file is saved, and displayed when that configuration file is reloaded. However, the external component
values are not used by the EVMCS for calculations.
6 Low Phase Noise Clock Evaluation Module — up to 1.5 GHz SCAU024 – September 2008
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