Transmitter Channel-To-Channel Skew; Receiver Skew Margin For Lvds Mode - Altera Cyclone V Device Handbook

CV-52005
2014.01.10
Receiver Channel Data Number

Transmitter Channel-to-Channel Skew

The receiver skew margin calculation uses the transmitter channel-to-channel skew (TCCS)—an important
parameter based on the Cyclone V transmitter in a source-synchronous differential interface:
TCCS is the difference between the fastest and slowest data output transitions, including the T
and clock skew.
For LVDS transmitters, the TimeQuest Timing Analyzer provides the TCCS value in the TCCS report
(
report_TCCS
You can also get the TCCS value from the device datasheet.
Related Information
Cyclone V Device Datasheet
LVDS SERDES Transmitter/Receiver (ALTLVDS_TX and ALTLVDS_RX) Megafunction User Guide
Provides more information about the LVDS Transmitter/Receiver Package Skew Compensation report
panel.

Receiver Skew Margin for LVDS Mode

In LVDS mode, use RSKM, TCCS, and sampling window (SW) specifications for high-speed source-
synchronous differential signals in the receiver data path.
The following equation expresses the relationship between RSKM, TCCS, and SW.
I/O Features in Cyclone V Devices
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5
6
7
8
9
10
11
12
13
14
15
16
17
18
) in the Quartus II compilation report, which shows TCCS values for serial output ports.
Transmitter Channel-to-Channel Skew
Internal 8-Bit Parallel Data
MSB Position
39
47
55
63
71
79
87
95
103
111
119
127
135
143
5-71
LSB Position
32
40
48
56
64
72
80
88
96
104
112
120
128
136
variation
CO
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