9DB433

FOUR OUTPUT DIFFERENTIAL BUFFER FOR PCIE GEN1–3

IDT®

FOUR OUTPUT DIFFERENTIAL BUFFER FOR PCIE GEN1–3

8

9DB433

MAY 25, 2018

Common Recommendations for Differential Routing

Dimension or Value

Unit

Figure

L1 length, route as non-coupled 50ohm trace

0.5 max

inch

1

L2 length, route as non-coupled 50ohm trace

0.2 max

inch

1

L3 length, route as non-coupled 50ohm trace

0.2 max

inch

1

Rs

33

ohm

1

Rt

49.9

ohm

1

Down Device Differential Routing

L4 length, route as coupled microstrip 100ohm differential trace 2 min to 16 max

inch

1

L4 length, route as coupled stripline 100ohm differential trace

1.8 min to 14.4 max

inch

1

Differential Routing to PCI Express Connector

L4 length, route as coupled microstrip 100ohm differential trace 0.25 to 14 max

inch

2

L4 length, route as coupled stripline 100ohm differential trace

0.225 min to 12.6 max

inch

2

Output Termination and Layout Information

HCSL Output Buffer

L1

L1'

Rs

L2

L2'

Rs

L4'

L4

L3

L3'

Rt

Rt

PCI Express

Down Device

REF_CLK Input

Figure 1: Down Device Routing

HCSL Output Buffer

L1

L1'

Rs

L2

L2'

Rs

L4'

L4

L3

L3'

Rt

Rt

PCI Express

Add-in Board

REF_CLK Input

Figure 2: Differential Routing to PCI Express Controller