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Table 7-10. PCI Express* DC Specifications
Symbol
V
TX-DIFF-p-p
V
TX_CM-AC-p
V
TX_CM-AC-p-p
Z
TX-DIFF-DC
Z
TX-DIFF-DC
Z
RX-DC
Z
RX-DIFF-DC
V
RX-DIFFp-p
V
RX-DIFFp-p
V
RX_CM-AC-p
PEG_ICOMPO
PEG_ICOMPI
PEG_RCOMPO
PEG_RBIAS
Notes:
1.
Refer to the PCI Express Base Specification for more details.
2.
V
TX-AC-CM-PP
at least 10^
3.
As measured with compliance test load. Defined as 2*|V
4.
COMP resistance must be provided on the system board with 1% resistors. COMP resistors are to V
5.
PEG_ICOMPO, PEG_ICOMPI, PEG_RCOMPO are the same resistor
6.
RMS value.
7.
Measured at Rx pins into a pair of 50-terminations into ground. Common mode peak voltage is defined by
the expression: max{|(Vd+ - Vd-) – V-CMDC|}.
8.
DC impedance limits are needed to guarantee Receiver detect.
9.
The Rx DC Common Mode Impedance must be present when the Receiver terminations are first enabled to
ensure that the Receiver Detect occurs properly. Compensation of this impedance can start immediately
and the 15 Rx Common Mode Impedance (constrained by RLRX-CM to 50 ±20%) must be within the
specified range by the time Detect is entered.
10. Low impedance defined during signaling. Parameter is captured for 5.0 GHz by RLTX-DIFF.
76
Alpha
Parameter
Group
(ad)
Differential peak to peak Tx
voltage swing
(ad)
Tx AC Peak Common Mode
Output Voltage (Gen1 only)
(ad)
Tx AC Peak-to-Peak Common
Mode Output Voltage (Gen2
only)
(ad)
DC Differential Tx Impedance
(Gen1 only)
(ad)
DC Differential Tx Impedance
(Gen2 only)
(ac)
DC Common Mode Rx
Impedance
(ac)
DC Differential Rx Impedance
(Gen1 only)
(ac)
Differential Rx input Peak to
Peak Voltage (Gen1 only)
(ac)
Differential Rx Input Peak to
Peak Voltage (Gen2 only)
(ac)
Rx AC peak Common Mode
Input Voltage
(ae)
Comp Resistance
(ae)
Comp Resistance
(ae)
Comp Resistance
(ae)
Comp Resistance
and V
are defined in the PCI Express Base Specification. Measurement is made over
TX-AC-CM-P
6
UI.
Electrical Specifications
Min
Typ
Max
0.8
—
1.2
—
—
20
—
—
100
80
—
120
—
—
120
40
—
60
80
—
120
0.175
—
1.2
0.120
—
1.2
—
—
150
49.5
50
50.5
49.5
50
50.5
49.5
50
50.5
742.5
750
757.5
– V
|.
TXD+
TXD-
Datasheet, Volume 1
1
Units
Notes
V
3
mV
1,2,6
mV
1,2
1,10
1,10
1,8,9
1
V
1
V
1,1
mV
1,7
4,5
4,5
4,5
4,5
.
SS
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