ICS557-01

PCI-EXPRESS GEN1 CLOCK SOURCE

PCIE

IDT® PCI-EXPRESS GEN1 CLOCK SOURCE

4

ICS557-01

REV P 072512

PCI-Express Layout Guidelines

Figure 1: PCI-Express Device Routing

Typical PCI-Express (HCSL) Waveform

Common Recommendations for Differential Routing

Dimension or Value

Unit

Figure

Notes

L1 length, Route as non-coupled 50 ohm trace.

0.5 max

inch

1,2

L2 length, Route as non-coupled 50 ohm trace.

0.2 max

inch

1,2

L3 length, Route as non-coupled 50 ohm trace.

0.2 max

inch

1,2

RS

33

ohm

1,2

RT

49.9

ohm

1,2

Differential Routing on a Single PCB

Dimension or Value

Unit

Figure

Notes

L4 length, Route as coupled microstrip 100 ohm differential trace.

2 min to 16 max

inch

1

L4 length, Route as coupled stripline 100 ohm differential trace.

1.8 min to 14.4 max

inch

1

Differential Routing to a PCI Express Connector

Dimension or Value

Unit

Figure

Notes

L4 length, Route as coupled microstrip 100 ohm differential trace.

0.25 to 14 max

inch

2

L4 length, Route as coupled stripline 100 ohm differential trace.

0.225 min to 12.6 max

inch

2

R

S

R

S

R

T

R

T

PCI-Express

Load or

Connector

L1

L2

L3’

L4

L1’

L2’

L3

L4’

ICS557-01

Output

Clock

0.175 V

0.52 V

0.175 V

0.52 V

t

OR

t

OF

500 ps

500 ps

700 mV

0