XRT8000_06 Datasheet, PDF (21/24 Pages) Exar Corporation – Clock Synchronizer/Adapter for Communications

XRT8000
8 kHz
XRT8000
F_IN
CLK1
CLK2
T1, T1/8
or
E1, E1/8
SYNC
8 kHz
Output Freq.
kHz
kHz
1544
193
2048
256
Figure 11. Slave Reverse Mode (Cont’d)
Board Layout Considerations
The CLK1 and CLK 2 outputs are surrounded with supply
pins (GND(514),Vcc(712). It is recommended to
decouple these supplies with a 0.1uF very close to the
pins. The positive supply (7,12,15) and ground pins
(4,5,14) can all be connected to the Digital Supply and
Ground.
The internal VCO has its proper supply’s pins (GND 9,
Vcc 10) these supply pins have to be decoupled by a
0.1uF capacitor and should be connected to an Analog
Supply if possible. If there is no Analog Supply, then
connect these pins as close as possible to the supply
source.
If the layout is done with separate layers for the supplies,
cut an island under the XTT8000 such that no current
flows under the circuit. It has been observed that coupling
can occur because heavy digital currents are flowing
under the locations of the XRT8000.
Rev. 1.11
21