Electrical Characteristics
MPC8610 Integrated Host Processor Hardware Specifications, Rev. 2
Freescale Semiconductor
63
2.18.4
Physical Layer Specifications
The following is a summary of the specifications for the physical layer of PCI Express on this device. For further details as well
as the specifications of the transport and data link layer, use the PCI Express Base Specification, Rev. 1.0a.
2.18.4.1
Differential Transmitter (TX) Output
Table 49 defines the specifications for the differential output at all transmitters (TXs). The parameters are specified at the
component pins.
Table 49. Differential Transmitter (TX) Output Specifications
Symbol
Parameter
Min
Nom
Max
Units
Comments
UI
Unit interval
399.88
400
400.12
ps
Each UI is 400 ps ± 300 ppm. UI does not account for
spread spectrum clock dictated variations. See Note 1
VTX-DIFFp-p
Differential
peak-to-peak
output voltage
0.8
1.2
V
VTX-DIFFp-p = 2*|VTX-D+ –VTX-D–| See Note 2
VTX-DE-RATIO
De- emphasized
differential
output voltage
(ratio)
-3.0
-3.5
-4.0
dB
Ratio of the VTX-DIFFp-p of the second and following
bits after a transition divided by the VTX-DIFFp-p of the
first bit after a transition. See Note 2
TTX-EYE
Minimum TX eye
width
0.70
UI
The maximum transmitter jitter can be derived as
TTX-MAX-JITTER = 1 – TTX-EYE= 0.3 UI.
See Notes 2 and 3
TTX-EYE-MEDIAN-to-
MAX-JITTER
Maximum time
between the jitter
median and
maximum
deviation from
the median.
0.15
UI
Jitter is defined as the measurement variation of the
crossing points (VTX-DIFFp-p = 0 V) in relation to a
recovered TX UI. A recovered TX UI is calculated over
3500 consecutive unit intervals of sample data. Jitter
is measured using all edges of the 250 consecutive UI
in the center of the 3500 UI used for calculating the TX
UI. See Notes 2 and 3
TTX-RISE, TTX-FALL
D+/D– TX output
rise/fall time
0.125
UI
See Notes 2 and 5
VTX-CM-ACp
RMS AC peak
common mode
output voltage
20
mV
VTX-CM-ACp = RMS(|VTXD+ –VTXD-|/2 – VTX-CM-DC)
VTX-CM-DC = DC(avg) of |VTX-D+ –VTX-D-|/2
See Note 2
VTX-CM-DC-ACTIVE-
IDLE-DELTA
Absolute delta of
DC common
mode voltage
during LO and
electrical idle
0
100
mV
|VTX-CM-DC (during LO) –VTX-CM-Idle-DC (During Electrical
Idle)|<=100 mV
VTX-CM-DC = DC(avg) of |VTX-D+ –VTX-D-|/2 [LO]
VTX-CM-Idle-DC = DC(avg) of |VTX-D+ –VTX-D-|/2
[Electrical Idle]
See Note 2
VTX-CM-DC-LINE-DELTA Absolute delta of
DC common
mode between
D+ and D–
025
mV
|VTX-CM-DC-D+ –VTX-CM-DC-D–| <= 25 mV
VTX-CM-DC-D+ = DC(avg) of |VTX-D+|
VTX-CM-DC-D– = DC(avg) of |VTX-D–|
See Note 2