User's Manual l MBLX2160A UM 0101 l © 2022, TQ-Systems GmbH
Page 27
3.9
Communication interfaces
All unspecified signals have a single-ended impedance of nominal 50 Ω ± 10 %.
Depending on the interface, other impedances are also used on the MBLX2160A.
Table 16:
MBLX2160A interface impedances
Interface
Impedance TQMLX2160A
Recommendation for carrier board
USB 3.0
90 Ω, differential
85 Ω ±15 %, differential
SerDes 1
100 Ω, differential
100 Ω ±10 %, differential
SerDes 2
100 Ω, differential
100 Ω ±10 %, differential
SerDes 3
90 Ω, differential
90 Ω ±15 %, differential
The layout guidelines of the respective standards are to be taken note of for the mainboard design.
FR-4 is used as PCB material for the MBLX2160A. Therefore the track lengths of the SerDes signals and the estimated insertion
losses have to be taken into consideration. The insertion losses are estimated as follows:
•
PCIe Gen 3
(4 GHz):
0.75 dB/Inch
•
XFI
(5.17 GHz):
0.85 dB/Inch
•
CAUI
(12.9 GHz):
2 dB/Inch
3.9.1
PCIe
There are 3 PCIe slots assembled on the MBLX2160A.
•
2 × PCIe ×4 (X35 and X36)
•
1 × PCIe ×8 (X37)
Figure 22:
PCIe slots arrangement
These three interfaces depend on the multiplexing and are not available without restrictions.
As described in chapter 3.5.1 the following options are possible:
•
PCIe ×4, X35:
o
×4 via SerDes #3 with muxing 3
•
PCIe ×4, X36:
o
×4 via SerDes #1 with muxing 14
o
×2 via SerDes #1 with muxing 12
