Channel Link Evaluation Kit User Manual
National Semiconductor Corporation
Interface Products
LIT# CLINK3V28BT-85-UM
Rev 2.1
Date: 10/12/2005
Page 9 of 28
Tx Board Options: 50 Ohm Termination for TxIN
On the Tx demo board, the 29 inputs have an option for 50 Ohm terminations.
There are 0402 pads for this purpose. One side is connected to the signal line and
the other side is tied to ground. These pads are unpopulated from the factory but
are provided if the user needs to install a 50 Ohm termination. R1 TO R28 are
associated with the Tx data input lines. R29 is associated with CLKIN. Some test
equipment may require a 50 Ohm load.
Mapping of Transmitter Inputs for the Optional Termination Resistors is shown
below:
Tx Pin
Names
Tx Pin
Number
Termination
Resistor
TxIN0 51
R1
TxIN1 52
R2
TxIN2 54
R3
TxIN3 55
R4
TxIN4 56
R5
TxIN5 2
R6
TxIN6 3
R7
TxIN7 4
R8
TxIN8 6
R9
TxIN9 7
R10
TxIN10 8
R11
TxIN11 10
R12
TxIN12 11
R13
TxIN13 12
R14
TxIN14 14
R15
TxIN15 15
R16
TxIN16 16
R17
TxIN17 18
R18
TxIN18 19
R19
TxIN19 20
R20
TxIN20 22
R21
TxIN21 23
R22
TxIN22 24
R23
TxIN23 25
R24
TxIN24 27
R25
TxIN25 28
R26
TxIN26 30
R27
TxIN27 50
R28
TxCLKIN 31
R29
50 Ohm Termination
(Optional)
TX