Revised
-
December 2013
LMK04906 Family: Low-Noise Clock Jitter with Dual Loop PLLs
SNAU126A
17
Copyright © 2013, 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
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
“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.