Table 8: Pci Express Insertion Loss Budget, 1.25 Ghz With Carrier Board Pcie Device; Table 9: Pci Express Insertion Loss Budget, 2.5 Ghz With Carrier Board Pcie Device - Advantech SOM-5992 Design Manual

Table 8 : PCI Express Insertion Loss Budget, 1.25 GHz with Carrier Board PCIe Device
Segment
Loss (dB)
max. Length
[mm/inches]
L 131/5.15
A
Coupling
Caps
L
B
L 402/15.85
C
Total 13.2
PCI Express Insertion Loss Budget, 2.5 GHz with Carrier Board PCIE Device
For "device down" PCIe Gen 2 operation, the Module PCIe maximum trace length is restricted to 5.0
inches and the Carrier Board maximum trace to 8.0 inches. Shorter lengths will yield additional margin
and are encouraged where possible. Results assumed FR4 dielectrics. Other dielectrics with lower
losses could be considered, but were not simulated.
Table 9 : PCI Express Insertion Loss Budget, 2.5 GHz with Carrier Board PCIe Device
Segment
max. Length
[mm/inches]
L 127/5
A
L
B
L 203/8
C
Total 330/13.0
Allowance for 3.46 dB loss @ 0.28 dB / GHz / inch and 1.66 dB crosstalk
allowance.
Coupling caps not included.
1.19 dB loss. From PCI Express Card Electromechanical Spec., Rev.
1.1, parameters (LST– LSR). Includes crosstalk allowance of 0.79 dB.
COM Express connector at 1.25 GHz measured value:
Allowance for 8.30 dB loss @ 0.28 dB / GHz / inch and a 2.75 dB
crosstalk allowance..
13.2dB loss
Allowance for module trace. Coupling cap effects included within simulation.
COM Express™ connector simulated at 2.5 GHz.
Allowance for Carrier Board trace.
PCIe GEN2 Data clocked architecture
３９
Notes
0.25 dB loss.
Notes