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Switching Characteristics
Table 23 lists the simulation data on the transmitter pre-emphasis levels in dB for the
first post tap under the following conditions:
■
low-frequency data pattern—five 1s and five 0s
data rate—2.5 Gbps
■
The levels listed are a representation of possible pre-emphasis levels under the
specified conditions only and the pre-emphasis levels may change with data pattern
and data rate.
Arria V devices only support 1st post tap pre-emphasis with the following conditions:
■
The 1st post tap pre-emphasis settings must satisfy |B| + |C| ≤60 where
|B| = VOD setting with termination value, RTERM = 100 Ωand |C| = 1st post tap
pre-emphasis setting
■
■
|B| – |C| > 5 for data rates < 5 Gbps and |B| – |C| > 8.25 for data rates
> 5 Gbps.
(VMAX/VMIN – 1)% < 600%, where VMAX = |B| + |C| and VMIN = |B| – |C|.
Exception for PCIe Gen2 design:
OD setting = 43 and pre-emphasis setting = 19 are allowed for PCIe Gen2 design
V
with transmit de-emphasis –6dB setting (pipe_txdeemp= 1’b0) using Altera PCIe
Hard IP and PIPE megafunctions.
For example, when VOD = 800 mV, the corresponding VOD value setting is 40. The
following conditions show that the 1st post tap pre-emphasis setting = 2 is a valid:
■
■
■
|B| + |C| ≤60 →40 + 2 = 42
|B| – |C| > 5 →40 – 2 = 38
(VMAX/VMIN – 1)% < 600% →(42/38 – 1)% = 10.52%
f
To predict the pre-emphasis level for your specific data rate and pattern, run
simulations using the Arria V HSSI HSPICE models.
Table 23. Transmitter Pre-Emphasis Levels for Arria V Devices (Part 1 of 2)
Quartus II VOD Setting
35
Quartus II 1st Post Tap
Pre-Emphasis Setting
Unit
10
(200 mV)
20
(400 mV)
30
(600 mV) (700 mV)
40
45
50
(800 mV) (900 mV) (1000 mV)
0
1
2
3
4
5
6
7
8
0
0
0
0
0
0
0
dB
dB
dB
dB
dB
dB
dB
dB
dB
1.97
3.58
5.35
7.27
—
0.88
1.67
2.48
3.31
4.19
5.08
5.99
6.92
0.43
0.95
1.49
2
0.32
0.76
1.2
0.24
0.61
1
0.19
0.5
0.13
0.41
0.69
0.96
1.26
1.56
1.87
2.11
0.83
1.14
1.49
1.83
2.18
2.48
1.63
2.1
1.36
1.76
2.17
2.58
2.93
2.55
3.11
3.71
4.22
—
2.56
3.06
3.47
—
—
Arria V GX, GT, SX, and ST Device Datasheet
December 2013 Altera Corporation
INTEL [ INTEL ]
