Intel Xeon Processor and Intel E7500/E7501Chipset Compatible Platform Design Guide

Hub Interface

106 Intel

Xeon™ Processor and Intel

E7500/E7501 Chipset Compatible Platform Design Guide

Hub Interface 2.0 has a minimum trace length requirement of 3 inches, and a maximum trace

length requirement of 20 inches for a device on the motherboard implementation for all hub

interface signals (using an internal routing layer on the recommended stack-up). However, for a

device on an adapter card plugged in a Hub Interface 2.0 connector, the maximum motherboard

trace length is 14 inches. (3 inches for card routing and 3 inches for connector skew.) For a riser

card topology, the maximum trace length would reduce by 3 inches to (11-Y) inches, where Y is

the riser card trace length. The riser must be built to not exceed the maximum trace length with the

motherboard routed length.

NOTE: The 14-inch maximum length allows for a single connector and 3-inch adaptor card trace length. The

PCI connector is an equivalent 3-inch electrical length. The maximum motherboard trace length must be

shortened if additional trace is allocated for the trace of a riser card, making sure to also subtract the

additional equivalent trace of a second connector.

Figure 7-3. Hub Interface 2.0 Routing Guidelines for Device Down Solutions

Figure 7-4. Hub Interface 2.0 Routing Guidelines for Hub Interface Connector Solutions

Intel

P64H2

CK408B

CLK66 CLK66

PSTRBF

PSTRBS

PUSTRBF

PUSTRBS

HI_[21:0]

3" – 20"