DS80PCI402 Datasheet, PDF (13/39 Pages) Texas Instruments – 2.5 Gbps / 5.0 Gbps / 8.0 Gbps 4 Lane PCI Express Repeater with Equalization and De-Emphasis

System Information
When using the DS80PCI402 in CPU systems, there are spe-
cific signal integrity settings to ensure signal integrity margin.
The settings were achieved with completing extensive test-
ing. Please contact your field representative for more infor-
mation regarding the testing completed to achieve these
settings.
For tuning the in the downstream direction (from CPU to EP).
• EQ: use the guidelines outlined in table 2.
Table 2: Equalizer Settings
• De-Emphasis: use the guidelines outlined in table 3.
• VOD: use the guidelines outlined in table 3.
For tuning in the upstream direction (from EP to CPU).
• EQ: use the guidelines outlined in table 2.
• De-Emphasis:
— For trace lengths < 15” set to -3.5 dB
— For trace lengths > 15” set to -6 dB
• VOD: set to 900 mV
Level
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
EQA1
EQB1
0
0
0
0
R
R
R
R
Float
Float
Float
Float
1
1
1
1
EQA0
EQB0
0
R
Float
1
0
R
Float
1
0
R
Float
1
0
R
Float
1
EQ – 8 bits [7:0]
0000 0000 = 0x00
0000 0001 = 0x01
0000 0010 = 0x02
0000 0011 = 0x03
0000 0111 = 0x07
0001 0101 = 0x15
0000 1011 = 0x0B
0000 1111 = 0x0F
0101 0101 = 0x55
0001 1111 = 0x1F
0010 1111 = 0x2F
0011 1111 = 0x3F
1010 1010 = 0xAA
0111 1111 = 0x7F
1011 1111 = 0xBF
1111 1111 = 0xFF
dB at
1.25 GHz
2.1
3.4
4.8
5.9
7.2
6.1
8.8
10.2
7.5
11.4
13.0
14.2
13.8
15.6
17.2
18.4
dB at
2.5 GHz
3.7
5.8
7.7
8.9
11.2
11.4
13.5
15.0
12.8
17.4
19.7
21.1
21.7
23.5
25.8
27.3
dB at
4 GHz
4.9
7.9
9.9
11.0
14.3
14.6
17.0
18.5
18.0
22.0
24.4
25.8
27.4
29.0
31.4
32.7
Suggested Use
FR4 < 5 inch trace
FR4 5 inch 5–mil trace
FR4 5 inch 4–mil trace
FR4 10 inch 5–mil trace
FR4 10 inch 4–mil trace
FR4 15 inch 4–mil trace
FR4 20 inch 4–mil trace
FR4 25 to 30 inch 4–mil trace
FR4 30 inch 4–mil trace
FR4 35 inch 4–mil trace
10m, 30awg cable
10m – 12m cable
13
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