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18
SNAU076B
LMK04800 Family
Revised - August 2014
Copyright © 2014, Texas Instruments Incorporated
Connector Name
Signal Type,
Input/Output
Description
Not populated:
OSCin, OSCin*
Analog,
Input
Feedback VCXO clock input to PLL1 and Reference
clock input to PLL2.
By default, these SMAs are not connected to the traces
going to the OSCin/OSCin* pins of the LMK048xxB.
Instead, the single-ended output of the onboard VCXO
(U2) drives the OSCin* input of the device and the
OSCin input of the device is connected to GND with
0.1 uF.
A VCXO add-on board may be optionally attached via
these SMA connectors with minor modification to the
components going to the OSCin/OSCin* pins of
device. This is useful if the VCXO footprint does not
accommodate the desired VCXO device.
A single-ended or differential signal may be used to
drive the OSCin/OSCin* pins and must be AC coupled.
If operated in single-ended mode, the unused input
must be connected to GND with 0.1 uF.
Refer to the
“Electrical Characteristics” for PLL2 Reference Input
(OSCin) specifications.
Test point:
VTUNE1_TP
Not populated:
Vtune1
Analog,
Output
Tuning voltage output from the loop filter for PLL1.
If a VCXO add-on board is used, this tuning voltage
can be connected to the voltage control pin of the
external VCXO when this SMA connector is installed
and connected through R72 by the user.
Test point:
VTUNE2_TP
Analog,
Output
Tuning voltage output from the loop filter for PLL2.
Populated:
uWire
Test points:
DATAuWire_TP
CLKuWIRE_TP
LEuWIRE_TP
CMOS,
Input/Output
10-pin header for uWire programming interface and
programmable logic I/O pins for the LMK048xxB.
The uWire interface includes CLKuWire,
DATAuWire, and LEuWire signals.
The programmable logic I/O signals accessible through
this header include: SYNC, Status_Holdover,
Status_LD, Status_CLKin0, and Status_CLKin1.
These logic I/O signals also have dedicated SMAs and
test points.