Datasheet

12 SNAU045A LMK040xx Evaluation Board User’s Guide November 2013
Copyright © 2013, Texas Instruments Incorporated
www.ti.com
Figure 3. LMK040xx with the XTAL Resonator option and Tuning Circuit
LMK040xxB evaluation boards are configured with a VCXO (NSID = LMK040xxEVAL) or crystal-based oscillator
circuit (NSID = LMK040xxEVAL-XO). The VCXO frequency is typically 122.88 MHz. The crystal frequency is
typically 12.288 MHz. These evaluation board instructions apply to either configuration. Figure 4 illustrates the
oscillator circuit based on a pullable crystal resonator.
Note that it is possible to place a VCXO or crystal on any evaluation board. The user may switch between
oscillator types by removing and replacing certain components on the board. Instructions for modifying the board
are presented in Appendix .
PLL2PLL1
R
1
Dq
1
N
1
R
2
N
2
Dq
2
VCO
CLKin0
CLKin1
VCO
DIV
CHAN
DIV
D
CHAN
DIV
D
5 Output Clock
Channels
LVPECL, LVDS,
LVCMOS
F
OUT
CLKout_0
CLKout_4
uWire
Interface
DATA
CLK
LE