１０５
2.13.2 SMB Routing Guidelines
The SMBus should be connected to all or none of the PCIe devices and slots. A general
recommendation is to not connect these devices to the SMBus.
The maximum load of SMBus lines is limited to 3 external devices. Please contact Advantech if more
devices are required.
Contact Advantech for a list of SMBus addresses used on the Module. Do not use the same address for
Carrier located devices.
2.13.3 SMB Trace Length Guidelines
Figure 32
: Topology for SMB
Table 38
: SMB Trace Length Guidelines
Parameter
Main Route Guidelines
Notes
Signal Group
SMB
Single End
50Ω ±15%
Nominal Trace Space within SPI
Signal Group
Min. 10mils
Spacing to Other Signal Group
Min. 10mils
LA
Please see the SOM-5992 Layout Checklist
LB
Carrier Board Length
Max length of LA+LB
24”
Length Mismatch
NA
Via Usage
Try to minimize number of vias
Notes:
