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Alternate Hardware Configurations
5.1.2
External LMK04828 Clock (Clock Distribution Mode)
The LMK04828 can be used as a clock distributor. In this case, the LMK04828 uses in input clock source
from CLKIN SMA connector (J12). JP2 (XO_PWR) can be left open to turn off the onboard VCXO to avoid
crosstalk. To use this mode, load the configuration file named
"LMK_Config_External_Clock.cfg”
. This
mode allows generation of frequencies that are not possible with the LMK when using the on-board
VCXO.
5.1.3
Clock Generator Using Onboard VCXO
The LMK04828 is used as a clock generator using the onboard 122.88-MHz VCXO. JP2 must be shorted
to turn on the onboard VCXO. The internal PLLs of the LMK04828 can be used with the onboard VCXO to
generate the desired frequencies. To use this mode, load one of the configuration files named
“LMK_Config_LMF_xxxx_yyyy_MSPS.cfg”
, where
xxxx
corresponds to the LMFS settings of the JESD
interface and
yyyy
corresponds to the desired ADC sampling rate. A 10-MHz signal can be brought into
the CLKIN input to synchronize to external instruments. This is the board default mode of operation.
15
SLAU641D – June 2015 – Revised January 2016
ADS5XJ6X Evaluation Module
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