Datasheet

6.1 Using the EVM GUI
www.ti.com TI CDCE62002 Control GUI Interface
The graphical layout of the EVM GUI is based on the functional structure of the CDCE62002. By means of
the EVM GUI the user can change the Input Frequency, Input Divider, Input type, Input selection, PFD
Charge Pump, Internal/External Loop Filter, Output MUX selection, Output Divider, and Output type. Other
configuration settings are selected by the software with user-selectable options as described in the steps
below. If the power to the CDCE62002 is derived from the USB, the “Enable EVM Power” check box must
be checked. If the power to the CDCE62002 is derived from an external source, the “Enable EVM Power”
check box must be unchecked.
Step 1: Primary Reference
The primary reference input buffer section on the GUI can be clicked for a popup window that opens up,
as displayed below, showing selections on the external input signal type (differential or single ended), the
external signal connection to the CDCE62002 primary inputs (AC or DC termination), input buffer 5K
internal termination (enabled or disabled).
Figure 2. Input Buffer Properties
Step 2: Reference Input Selection through Smart MUX
The Smart MUX section of the GUI can be clicked for a popup window that opens up, as displayed below,
showing selections between PRI SEL (Primary Reference Select), AUX SEL (Auxiliary Input Select), or
AUTO Select between Primary Reference and Auxiliary Input with a preference to Primary Reference. A
Reference divider up to divide by 16 is available for the Primary Reference. In order for the Smart Mux to
work correctly in auto Mode the primary reference frequency should after the divider should be within 20%
of the frequency of the auxiliary input.
Figure 3. Smart MUX
Step 3: Input Divider Selection and PFD frequency
The Smart MUX section output feeds the input divider block where the signal can be divided up to 256.
The input divider output feeds the PFD. The output frequency of the input divider is what referred to is the
PFD frequency.
Figure 4. Smart MUX
SCAU034 – June 2009 Two/Four Output Low Phase Noise Clock Evaluation Board 5
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