ICS557-03
PCI-EXPRESS CLOCK SOURCE
PCI-Express Layout Guidelines
Common Recommendations for Differential Routing
Dimension or Value Unit
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.
RS
RT
0.5 max
0.2 max
0.2 max
33
inch
inch
inch
ohm
ohm
49.9
Differential Routing on a Single PCB
Dimension or Value Unit
L4 length, Route as coupled microstrip 100 ohm differential trace.
L4 length, Route as coupled stripline 100 ohm differential trace.
2 min to 16 max
1.8 min to 14.4 max
inch
inch
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 Unit
0.25 to 14 max inch
0.225 min to 12.6 max inch
PCI-Express Device Routing
L1
L2
L4
RS
RS
L4’
L1’
L2’
RT
RT
PCI-Express
Load or
Connector
ICS557-03
Output
L3’ L3
Clock
Typical PCI-Express (HCSL)
Waveform
700 mV
0
500 ps
500 ps
tOR
tOF
0.52 V
0.175 V
0.52 V
0.175 V
MDS 557-03 E
4
Revision 061005
Integrated Circuit Systems ● 525 Race Street, San Jose, CA 95126 ● tel (408) 297-1201 ● www.icst.com
ICSI [ INTEGRATED CIRCUIT SOLUTION INC ]
