DS50PCI402_14 Datasheet, PDF (6/35 Pages) Texas Instruments – 2.5 Gbps / 5.0 Gbps 4 Lane PCI Express Repeater with Equalization and De-Emphasis

DS50PCI402
SNLS320G – APRIL 2010 – REVISED MAY 2011
www.ti.com
Table 1. Equalization Settings with GST=1 for Pins or SMBus Registers (continued)
EQ1
EQ0
EQ Setting
GST[1 BST[2:
:0]
0]
EQ Gain (dB)
1.25 GHz
2.5 GHz
Suggested Use
01
101
4.9
7.9
01
110
5.4
8.5
01
111
5.6
9.0
F=Float (don't drive pin, each float pin has an internal 50K Ohm resistor to VDD and GND), 1=High, 0=Low
Table 2. Equalization Settings with GST=2 for Pins or SMBus Registers
EQ1
0
F
F
0
EQ0
0
0
1
1
EQ Setting
GST[1 BST[2:
:0]
0]
EQ Gain (dB)
1.25 GHz
2.5 GHz
Suggested Use
10
000
3.8
7.6
14" FR4 (6-mil trace) or 1m (28 AWG) PCIe cable
10
001
5.1
9.9
10
010
6.4
11.6
20" FR4 (6-mil trace) or 5m (26 AWG) PCIe cable
10
011
7.6
13.5
10
100
9.5
16.1
10
101
11.3
17.5
40" FR4 (6-mil trace) or 9m (24 AWG) PCIe cable
10
110
12.3
18.6
10
111
12.8
19.8
50" FR4 (6-mil trace) or 10m (24 AWG) PCIe cable
F=Float (don't drive pin, each float pin has an internal 50K Ohm resistor to VDD and GND), 1=High, 0=Low
Table 3. Equalization Settings with GST=3 for Pins or SMBus Registers
EQ1
1
0
1
EQ0
0
F
F
EQ Setting
GST[1 BST[2:
:0]
0]
EQ Gain (dB)
1.25 GHz
2.5 GHz
Suggested Use
11
000
6.4
12.2
11
001
8.5
15.6
30" FR4 (6-mil trace) or 7m (24 AWG) PCIe cable
11
010
10.4
18.3
11
011
12.4
21.3
15m (24 AWG) PCIe cable
11
100
15.2
25.0
11
101
18.1
27.2
> 15m (24 AWG) PCIe cable
11
110
19.6
28.8
11
111
20.2
30.7
F=Float (don't drive pin, each float pin has an internal 50K Ohm resistor to VDD and GND), 1=High, 0=Low
The De-Emphasis level must be set when in SMBus mode. See SMBus TRANSACTIONS section and
Table 9 for specific De-Emphasis values.
RATE
0/F
0/F
0/F
0/F
0/F
0/F
0/F
Table 4. De-Emphasis Input Select Pins for A and B ports (3–Level Input)
DEM1 DEM0
0
0
0
1
Typical De-
Emphasis Level
0dB
-3.5dB
Typical DE Pulse
Width
0ps
400ps
Typical VOD
1000mV
1000mV
1
0
1
1
0
F
1
F
F
0
-6dB
-6dB
-9dB
-12dB
-9dB
400ps
400ps enhanced
400ps enhanced
400ps enhanced
400ps enhanced
1000mV
1000mV
1000mV
1000mV
1200mV
Suggested Use
8 inches FR4 (6-mil trace) or less than 1
meter (28 AWG) PCIe cable
15 inches FR4 (6-mil trace)
30 inches FR4 (6-mil trace)
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