Channel Link Evaluation Kit User Manual
National Semiconductor Corporation
Interface Products
LIT# CLINK3V28BT-85-UM
Rev 2.1
Date: 10/12/2005
Page 14 of 28
Rx Optional: Series Termination for RxOut
On the Rx demo board, there are 29 outputs that have an 0402 pad in series (which
are shorted out). These pads are unpopulated from the factory but are provided if
the user needs to install a 450 Ohm series resistors. This is required if directly
connecting to 50 Ohm inputs on a scope. To use this option the user must cut the
signal line between the pads before installing the 450 Ohm series resistors. R1 to
R28 are associated with the DATA output lines. R29 is associated with CLKOUT.
The total load presented to the receiver output is 500 Ohms (450 + 50). The
waveform on the scope is 1/10 of the signal due to the resulting voltage divider (50 /
(450 + 50)).
Optional Series Termination Resistor mapping is shown below:
Rx Pin Names Rx Pin
Number
Series
Termination
Resistor
RxOUT0 27 R28
RxOUT1 29 R27
RxOUT2 30 R26
RxOUT3 32 R25
RxOUT4 33 R24
RxOUT5 34 R23
RxOUT6 35 R22
RxOUT7 37 R21
RxOUT8 38 R20
RxOUT9 39 R19
RxOUT10 41
R18
RxOUT11 42
R17
RxOUT12 43
R16
RxOUT13 45
R15
RxOUT14 46
R14
RxOUT15 47
R13
RxOUT16 49
R12
RxOUT17 50
R11
RxOUT18 51
R10
RxOUT19 53
R9
RxOUT20 54
R8
RxOUT21 55
R7
RxOUT22 1
R6
RxOUT23 2
R5
RxOUT24 3
R4
RxOUT25 5
R3
RxOUT26 6
R2
RxOUT27 7
R1
RxCLKOUT 26
R29
RX
Series Termination
(Optional)
