Electrical Characteristics
4.3.1.2
Differential Receiver (RX) Input Specifications
Table 4-17 defines the specifications of parameters for all differential Receivers (RXs). The
parameters are specified at the component pins.
Table 4-17. Differential Receiver (RX) Input Specifications
Symbol
Parameter
Min
Nom
Max
Units Comments
UI
Unit Interval
399.88
400
400.12
ps
The UI is 400 ps +/-300 ppm. UI does
not account for SSC dictated
variations.
See Note 1.
TRX-EYE
Minimum
Receiver Eye
Width
0.4
UI
The maximum interconnect media and
transmitter jitter that can be tolerated
by the receiver can be derived as
T
RX-MAX-JITTER =1 -TRX-EYE =0.6 UI
See Notes 2 and 3.
TRX-EYE-
Maximum time
between the
jitter median
and maximum
deviation from
the median.
0.3
UI
Jitter is defined as the measurement
variation of the crossing points
(VRX- DIFFp-p = 0 V)
in relation to an appropriate average
TX UI.
MEDIAN-to-
MAX-
JITTER
See Notes 2 and 3.
TRX-IDLE-
Unexpected
Electrical Idle
Enter Detect
Threshold
10
20
ms
ns
An unexpected electrical idle
(VRX-DIFFp-p <VRX-IDLE-DET- DIFFp-p
must be recognized no longer than
TRX-IDLE-DET- DIFF-ENTERTIME to signal
an unexpected idle condition.
)
DET-DIFF-
ENTERTIME
Integration Time
LRX-SKEW
Total Skew
Across all Lanes on a port. This
includes variation in the length of a skip
ordered-set (e.g., COM and 1 to 5 SKP
symbols) at the RX as well as any
delay differences arising from the
interconnect itself.
NOTES:
1. No test load is necessarily associated with this value.
2. Specified at the measurement point and measured over any 250 consecutive UIs. The test load in Figure 4-2
should be used as the RX device when taking measurements (also refer to the Receiver Compliance Eye
Diagram as shown in Figure 4-3). If the clocks to the RX and TX are not derived from the same clock chip the
TX UI must be used as a reference for the eye diagram.
3. A TRX-EYE = 0.40 UI provides for a total sum of 0.60 UI deterministic and random jitter budget for the
transmitter and interconnect collected any 250 consecutive UIs. The TRX-EYE-MEDIAN-to-MAX-JITTER
specification ensures a jitter distribution in which the median and the maximum deviation from the median is
less than half of the total 0.60 UI jitter budget collected over any 250 consecutive TX UIs. It should be noted
that the median is not the same as the mean. The jitter median describes the point in time where the number
of jitter points on either side is approximately equal as opposed to the averaged time value. If the clocks to
the RX and TX are not derived from the same clock chip, the appropriate average TX UI must be used as the
reference for the eye diagram.
Intel® 6702PXH 64-bit PCI Hub Datasheet
169
INTEL [ INTEL ]
