Electrical Specifications
102
Datasheet
NOTES:
1.
Refer to the
PCI Express Base Specification
for more details.
2.
V
TX-AC-CM-PP
and V
TX-AC-CM-P
are defined in the
PCI Express Base Specification
. Measurement is made over
at least 10^
6
UI.
3.
As measured with compliance test load. Defined as 2*|V
TXD+
- V
TXD-
|.
4.
COMP resistance must be provided on the system board with 1% resistors. COMP resistors are to V
SS
.
5.
PEG_ICOMPO, PEG_ICOMPI, PEG_RCOMPO are the same resistor
6.
RMS value.
7.
Measured at Rx pins into a pair of 50-
Ω
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
Ω
±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.
Table 7-45.PCI Express DC Specifications
Symbol
Alpha
Group
Parameter
Min
Typ
Max
Units
Notes
1
V
TX-DIFF-p-p
(ad)
Differential Peak-to-Peak Tx Voltage
Swing
0.8
1.2
V
3
V
TX_CM-AC-p
(ad)
Tx AC Peak Common Mode Output
Voltage (Gen 1 Only)
20
mV
1,2,6
Z
TX-DIFF-DC
(ad)
DC Differential Tx Impedance
(Gen 1 Only)
80
120
Ω
1,10
Z
RX-DC
(ac)
DC Common Mode Rx Impedance
40
60
Ω
1,8,9
Z
RX-DIFF-DC
(ac)
DC Differential Rx Impedance
(Gen1 Only)
80
120
Ω
1
V
RX-DIFFp-p
(ac)
Differential Rx Input Peak-to-Peak
Voltage (Gen 1 only)
0.175
1.2
V
1,11
V
RX_CM-AC-p
(ac)
Rx AC Peak Common Mode Input
Voltage
150
mV
1,7
PEG_ICOMPO
(ae)
Comp Resistance
49.5
50
50.5
Ω
4,5
PEG_ICOMPI
(ae)
Comp Resistance
49.5
50
50.5
Ω
4,5
PEG_RCOMPO (ae)
Comp Resistance
49.5
50
50.5
Ω
4,5
PEG_RBIAS
(ae)
Comp Resistance
742.5
750
757.5
Ω
4,5
