ICS557-03
PCI-E
XPRESS
C
LOCK
S
OURCE
PCI-Express Layout Guidelines
Common Recommendations for Differential Routing
L1 length, Route as non-coupled 50 ohm trace.
L2 length, Route as non-coupled 50 ohm trace.
L3 length, Route as non-coupled 50 ohm trace.
R
S
R
T
Differential Routing on a Single PCB
L4 length, Route as coupled
microstrip
100 ohm differential trace.
L4 length, Route as coupled
stripline
100 ohm differential trace.
Differential Routing to a PCI Express Connector
L4 length, Route as coupled
microstrip
100 ohm differential trace.
L4 length, Route as coupled
stripline
100 ohm differential trace.
Dimension or Value
0.5 max
0.2 max
0.2 max
33
49.9
Dimension or Value
2 min to 16 max
1.8 min to 14.4 max
Dimension or Value
0.25 to 14 max
0.225 min to 12.6 max
Unit
inch
inch
inch
ohm
ohm
Unit
inch
inch
Unit
inch
inch
PCI-Express Device Routing
L1
R
S
L1’
R
S
L2
L2’
R
T
L3’
R
T
L3
L4
L4’
ICS557-03
Output
Clock
PCI-Express
Load or
Connector
Typical PCI-Express (HCSL)
Waveform
700 mV
0
t
OR
0.52 V
0.175 V
500 ps
500 ps
t
OF
0.52 V
0.175 V
MDS 557-03 E
In te grated Circuit Systems
●
4
525 Ra ce Street, San Jose, CA 9512 6
●
Revision 061005
tel (4 08) 297-1 201
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ICS [ INTEGRATED CIRCUIT SYSTEMS ]
