Evaluation Board Inputs and Outputs
11
SNAU200 – September 2016
Copyright © 2016, Texas Instruments Incorporated
LMK04208 User’s Guide
7
Evaluation Board Inputs and Outputs
contains descriptions of the inputs and outputs for the evaluation board. Unless otherwise noted,
the connectors described can be assumed to be populated by default. Additionally, some applicable TICS
Pro programming controls are noted for convenience.
Table 5. Description of Evaluation Board Inputs and Outputs
CONNECTOR NAME
SIGNAL TYPE,
INPUT/OUTPUT
DESCRIPTION
Populated:
CLKout0, CLKout0*,
CLKout1, CLKout1*,
CLKout4, CLKout4*,
CLKout5, CLKout5*
Analog,
Output
Clock outputs with programmable output buffers.
Default output terminations on the evaluation board are shown below:
Clock Output
Default Board Termination
CLKout0
240
Ω
emitter resistor, LVPECL
CLKout1
open, LVDS/LVCMOS
CLKout2
240
Ω
emitter resistor, LVPECL
CLKout3
240
Ω
emitter resistor, LVPECL
CLKout4
open, LVDS/LVCMOS
CLKout5
240
Ω
emitter resistor, LVPECL
Not Populated:
CLKout2, CLKout2*,
CLKout3, CLKout3*
Each CLKout has a programmable LVDS, LVPECL, or LVCMOS output buffer. The
output buffer type can be selected in TICS Pro on the Clock Outputs page via the
CLKoutX_TYPE control.
All clock outputs are AC-coupled to allow safe testing with RF test equipment.
If an output is programmed to LVCMOS, each output can be independently
configured (normal, inverted, or off/tri-state). Best performance/EMI reduction is
achieved by using a complementary output mode like Norm/Inv. It is NOT
recommended to use Norm/Norm or Inv/Inv mode.
Populated:
OSCout, OSCout*
Analog,
Output
Buffered output of OSCin port.
The output terminations on the evaluation board are shown below.:
OSC Output
Default Board Termination
OSCout
open, LVDS/LVCMOS
OSCout has a programmable LVDS, LVPECL, or LVCMOS output buffer. The
output buffer type can be selected in TICS Pro on the Clock Outputs page via the
OSCout_TYPE control.
OSCout is AC-coupled to allow safe testing with RF test equipment.
If OSCout is programmed as LVCMOS, each output can be independently
configured (normal, inverted, inverted, and off/tri-state). Best performance/EMI
reduction is achieved by using a complementary output mode like Norm/Inv. It is
NOT recommended to use Norm/Norm or Inv/Inv mode.
Populated:
Vcc
Power,
Input
Main power supply input for the evaluation board.
The LMK04208 contains internal voltage regulators for the VCO, PLL and other
internal blocks. The clock outputs do not have an internal regulator, so a clean
power supply with sufficient output current capability is required for optimal
performance.
On-board LDO regulators and 0
Ω
resistor options provide flexibility to supply and
route power to various devices. See the schematics in section
for more
details.
Apply power to either Vcc SMA or J1, but not both.
Populated:
J1
Power,
Input
Alternative power supply input for the evaluation board using two unshielded wires
(Vcc and GND).
Apply power to either Vcc SMA or J1, but not both.
Not Populated:
VccVCXO/Aux
Power,
Input
Optional Vcc input to power the VCXO circuit if separated voltage rails are needed.
The VccVCXO/Aux input can power these circuits directly or supply the on-board
LDO regulators. 0
Ω
resistor options provide flexibility to route power.
This connector is on the bottom of the PCB.
