L M K 0 4 9 0 6 E V A L U A T I O N B O A R D O P E R A T I N G I N S T R U C T I O N S
SNAU126
16
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 LMK04906B.
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
LMK04906 Family Datasheet
section
“Electrical Characteristics” for PLL2 Reference Input
(OSCin) specifications.
Test point:
VTUNE1_TP
Analog,
Output
Tuning voltage output from the loop filter for PLL1.
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 LMK04906B.
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.