Texas Instruments LMK00304 Evaluation Board LMK00304EVM/NOPB LMK00304EVM/NOPB Datenbogen
Produktcode
LMK00304EVM/NOPB
8
LM
K00304EVM User’s Guide
March 2012
9. Clock Outputs
By default, Bank A and Bank B outputs are configured for LVPECL mode, and are source-terminated with
160 ohm resistors and AC coupled to the SMA connectors labeled CLKoutA#+ / CLKoutA#- and CLKoutB#+ /
CLKoutB#-. To modify the output interface for a different output mode, refer to the modifications noted in the
160 ohm resistors and AC coupled to the SMA connectors labeled CLKoutA#+ / CLKoutA#- and CLKoutB#+ /
CLKoutB#-. To modify the output interface for a different output mode, refer to the modifications noted in the
REFout is a LVCMOS output and is AC coupled to its SMA connector.
As noted before, active output traces should be properly terminated; otherwise any unused output pin can be
disconnected from the output trace by removing the 0-ohm series resistor.
9.1. LVPECL and LVCMOS with 2.5 V Vcco
The LVPECL and LVCMOS output levels depend on the outpu
t driver’s respective Vcco supply as specified
in the datasheet.
When an output bank is configured for LVPECL and its Vcco supply is 2.5 V, it is suggested to replace the
160-ohm
When an output bank is configured for LVPECL and its Vcco supply is 2.5 V, it is suggested to replace the
160-ohm
-termination resistor to ground with a lower value, such as 91 ohms, to maintain proper DC
bias current on each output.