DS80PCI402_15 Datasheet, PDF (15/54 Pages) Texas Instruments – 2.5-Gbps / 5.0-Gbps / 8.0-Gbps 4-Lane PCI-Express Repeater With Equalization and De-Emphasis

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DS80PCI402
SNLS324E – APRIL 2011 – REVISED JANUARY 2015
Table 3. Output Voltage and De-Emphasis Settings⁽¹⁾
LEVEL
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
DEMA1
DEMB1
0
0
0
0
R
R
R
R
Float
Float
Float
Float
1
1
1
1
DEMA0
DEMB0
0
R
Float
1
0
R
Float
1
0
R
Float
1
0
R
Float
1
VOD Vp-p
0.8
0.9
0.9
1.0
1.0
1.0
1.1
1.1
1.1
1.2
1.2
1.2
1.3
1.3
1.3
1.3
DEM dB
(see ⁽¹⁾)
0
0
–3.5
0
–3.5
–6
0
–3.5
–6
0
–3.5
–6
0
–3.5
–6
–9
INNER AMPLITUDE
Vp-p
0.8
0.9
0.6
1.0
0.7
0.5
1.1
0.7
0.6
1.2
0.8
0.6
1.3
0.9
0.7
0.5
SUGGESTED USE
FR4 < 5 inch 4-mil trace
FR4 < 5 inch 4-mil trace
FR4 10 inch 4-mil trace
FR4 < 5 inch 4-mil trace
FR4 10 inch 4-mil trace
FR4 15 inch 4-mil trace
FR4 < 5 inch 4-mil trace
FR4 10 inch 4-mil trace
FR4 15 inch 4-mil trace
FR4 < 5 inch 4-mil trace
FR4 10 inch 4-mil trace
FR4 15 inch 4-mil trace
FR4 < 5 inch 4-mil trace
FR4 10 inch 4-mil trace
FR4 15 inch 4-mil trace
FR4 20 inch 4-mil trace
(1) The VOD output amplitude and DEM de-emphasis levels are set with the DEMA/B[1:0] pins.
The de-emphasis levels are available in GEN1, GEN2, and GEN 3 modes when RATE = Float.
PRSNT ⁽¹⁾
(PIN 52)
0
0
0
0
1
RXDET
(PIN 22)
0
Tie 20 kΩ
to GND
Float
(Default)
1
X
Table 4. RX-Detect Settings
SMBus REG
BIT[3:2]
00
01
10
11
INPUT TERMINATION COMMENTS
Hi-Z
Pre Detect: Hi-Z
Post Detect: 50 Ω
Pre Detect: Hi-Z
Post Detect: 50 Ω
50 Ω
Hi-Z
Manual RX-Detect, input is high-impedance mode
Auto RX-Detect, outputs test every 12 ms for 600 ms
then stops; termination is hi-Z until detection; once
detected input termination is 50 Ω
Reset function by pulsing PRSNT high for 5 µs then
low again
Auto RX-Detect, outputs test every 12 ms until
detection occurs; termination is hi-Z until detection;
once detected input termination is 50 Ω
Reset function by pulsing PRSNT high for 5 µs then
low again
Manual RX-Detect, input is 50 Ω
Power-down mode, input is high impedance, output
drivers are disabled
Used to reset RX-Detect State Machine when held
high for 5 µs
(1) In SMBus Slave Mode, the Rx Detect State Machine can be manually reset in software by overriding the device PRSNT function. This is
accomplished by setting the Override RXDET bit (Reg 0x02[7]) and then toggling the RXDET Value bit (Reg 0x02[6]). See Table 9 for
more information about resetting the Rx Detect State Machine.
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