Electrical characteristics
The DC and AC specification of SerDes data lanes are defined in each interface protocol
section below based on the application usage:
• PCI Express
• Serial RapidIO (sRIO)
• XAUI interface
• Aurora interface
• Serial ATA (SATA) interface
• SGMII interface
• HiGig/HiGig2 interface
• XFI interface
• 10GBase-KR interface
• 1000Base-KX interface
Note that external AC-coupling capacitor is required for the above serial transmission
protocols with the capacitor value defined in the specification of each protocol section.
3.19.4 PCI Express
This section describes the clocking dependencies, DC and AC electrical specifications for
the PCI Express bus.
3.19.4.1 Clocking dependencies
The ports on the two ends of a link must transmit data at a rate that is within 600 parts per
million (ppm) of each other at all times. This is specified to allow bit rate clock sources
with a ±300 ppm tolerance.
3.19.4.2 PCI Express clocking requirements for SDn_REF_CLKn_P and
SDn_REF_CLKn_N
SerDes 1-2 (SD[1:2]_REF_CLK[1:2]_P and SD[1:2]_REF_CLK[1:2]_N) may be used
for various SerDes PCI Express configurations based on the RCW Configuration field
SRDS_PRTCL. PCI Express is not supported on SerDes 1 and 2.
NOTE
PCI Express operating in x8 mode is only supported at 2.5 and
5.0 GT/s.
For more information on these specifications, see SerDes reference clocks.
QorIQ T2080 Data Sheet, Rev. 3, 03/2018
NXP Semiconductors
107