15. Electrical Characteristics > AC Timing Specifications
223
PEB383 User Manual
July 25, 2011
Integrated Device Technology, Inc.
Confidential - NDA Required
15.6.2
PCIe Differential Transmitter Output Specification
The following table lists the specification of parameters for the differential output of the PCIe lanes.
Table 47: PCIe Differential Transmitter Output Specification
Symbol
Parameter
Min.
Nom.
Max.
Units
Comments
UI
Unit Interval
399.88
400
400.12
ps
Each UI is 400ps +/-300ppm. UI
does not account for SSC dictated
variations. See Note 1.
V
TX-DIFFp-p
Differential Peak to
Peak Output Voltage
programmed to
tx_lvl=5b’01001 and
tx_boost = 0
0.800
-
1.2
V
V
TX-DIFFp-p
= 2*|V
TX-D+
- V
TX-D-
|
See Note 1.
V
TX-DE-RATIO
De-emphasized
Differential Output
Voltage (Ratio)
-3.0
-3.5
-4.0
dB
This is the ratio of the V
TX-DIFFp-p
of
the second and following bits after a
transition divided by the V
TX-DIFFp-p
of the first bit after a transition.
See Note 2
T
TX-EYE
Minimum TX Eye
Width
0.75
-
-
UI
The maximum Transmitter jitter can
be derived as T
TX-MAX-JITTER
= 1 -
T
TX-EYE
= 0.25 UI.
This parameter is measured with the
equivalent of a zero jitter reference
clock. See Notes 2 and 3.
T
TX-EYE-MEDIAN-
to-MAX-JITTER
Maximum time
between the jitter
median and maximum
deviation from the
median
-
-
0.125
UI
Jitter is defined as the measurement
variation of the crossing points
(V
TX-DIFF
= 0V) in relation to
recovered TX UI.
To be measured after the clock
recovery function in Section 4.3.3.2
of the
PCI Express Base
Specification Rev 1.1
. See Notes 2
and 3.
T
TX-RISE
, T
TX-FALL
D+/D- TX Output
Rise/Fall Time
0.125
-
-
UI
See Notes 2 and 5.
V
TX-CM-ACp
RMS AC Peak
Common Mode Output
Voltage
-
-
20
mV
V
TX-CM-ACp
= RMS(|V
TX-D+
+
V
TX-D-
|/2 - V
TX-CM-DC
)
V
TX-CM-DC
= DC
(AVG)
of |V
TX-D+
+
V
TX-D-
|/2
See Note 2
V
TX-CM-DC-ACTIVE-
IDLE-DELTA
Absolute Delta of DC
Common Mode
Voltage During L0 and
Electrical Idle
0
-
100
mV
|V
TX-CM-DC [during L0]
-V
TX-CM-DC
[during electrical idle]
| <= 100mV
V
TX-CM-DC
= DC
(AVG)
of |V
TX-D+
+
V
TX-D-
|/2 [L0]
V
TX-CM-idle-DC
= DC
(AVG)
of |V
TX-D+
+
V
TX-D-
|/2 [Electrical Idle]
See Note 2