© 2005 Fairchild Semiconductor
Page 5
of 9
Rev 1.0 December 2005
www.fairchildsemi.com
4.2 Connecting Power to the Board
Each board has two power supply connections, plus ground. When the flex cable supplied is utilized,
power from one board is fed to the other board through the flex. Consequently, only one board needs
to be powered. All power supplies must be connected to an appropriate voltage range. Table 2 lists
typical voltages utilized. An LED on each board confirms the operation of the power supply.
Note 1:
An LED may illuminate rather dimly with a power supply set to a low setting. In addition,
if power is connected to the board on only 1 side, a brief glance at the LEDs on the opposite will show
that the flex is connected correctly and supplying power to the opposite side.
Note 2:
The power supplies between sections of the board are connected together by default.
(VDDP Board 1 to VDDP Board 2, and VDDS/VDDA Board 1 to VDDS/VDDA Board 2))
Note 3:
For proper operation, make sure all power supplies are activated before input signal is
provided to the serializer.
Table 2: Voltage Ranges
4.3 Flex Connection
The flex connectors have a limited insertion/removal life. Consequently, it is not advisable to insert
and remove the cable repeatedly. In addition, the flex cable supplied by Fairchild should be the only
one used with this board. Please contact your Fairchild µSerDes representative to obtain a cable of
different specifications.
The flex cable may be inserted or removed, but must be done so with care. To do so, gently slide the
flex cable connector snap away from the board and remove the flex cable. When inserting the flex
cable, ensure that the connector snap is first in the unlatched position (toward the outside of the
board). Gently insert the cable with the contacts facing
upward
.
Note:
An inadvertent short of power supplies on opposite sides of the board while connecting cables
may result in extreme current passing through the board and flex cable, which may render the flex
cable intermittent or inoperative. Be sure to turn off power before connecting the flex cable.
Name
Description
V
DDA
Voltage Reference Supply Range: 2.5V to 2.9V
V
DDS
Supply Voltage for the Core and Serial I/O. Must be at 2.5V to 2.9V
V
DDP
Parallel and Translation Supply Range: 1.65V to 3.6V
Ground
Common to all supplies, and to µSerDes ground slug beneath the par t.
