DS80PCI800SQ Datasheet, PDF (13/45 Pages) Texas Instruments – DS80PCI800 2.5 Gbps / 5.0 Gbps / 8.0 Gbps 8 Channel PCI Express Repeater

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DS80PCI800
SNLS334E – APRIL 2011 – REVISED MARCH 2012
3.3V mode
Enable
VDD_SEL
Internal
voltage
regulator
2.5V
VIN
VDD
VDD
VDD
2.5V mode
Disable
VDD_SEL
open
3.3V
Capacitors can be
either tantalum or an
ultra-low ESR seramic.
Internal
voltage
regulator
0.1 uF
0.1 uF
0.1 uF
VIN
open
VDD
0.1 uF
2.5V
VDD
VDD
0.1 uF
Capacitors can be
either tantalum or an
ultra-low ESR seramic.
0.1 uF
VDD
0.1 uF
VDD
0.1 uF
Place 0.1 uF close to VDD Pin
Total capacitance should be 7 0.5 uF
VDD
0.1 uF
VDD
0.1 uF
Place capcitors close to VDD Pin
Figure 6. 3.3V or 2.5V Supply Connection Diagram
System Information
When using the DS80PCI800 in CPU systems, there are specific signal integrity settings to ensure signal
integrity margin. The settings were achieved with completing extensive testing. Please contact your field
representative for more information 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.
• 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
EQA1
EQB1
0
EQA0
EQB0
0
Table 2. Equalizer Settings
EQ – 8 bits [7:0]
0000 0000 = 0x00
dB at
1.25 GHz
2.1
dB at
2.5 GHz
3.7
dB at
4 GHz
4.9
Suggested Use
FR4 < 5 inch trace
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