Vol 1

Intel® Xeon® Product 2800/4800/8800 v2 Product Family 107
Datasheet Volume One, February 2014
Electrical Specifications
6.12.2 I/O Signal Quality Specifications
Signal Quality specifications for PCIe Signals are included as part of the PCIe DC
specifications and PCIe AC specifications. Various scenarios have been simulated to
generate a set of layout guidelines.
6.12.3 Intel
®
QuickPath Interconnect Signal Quality
Specifications
Signal Quality specifications for Differential Intel® QuickPath Interconnect Signals are
included as part of the Intel QuickPath Interconnect defined in the Intel® QuickPath
Interconnect V1.1 Base Electrical Specification and Validation Methodologies. Various
scenarios have been simulated to generate a set of layout guidelines.
6.12.4 Input Reference Clock Signal Quality Specifications
Overshoot/Undershoot and Ringback specifications for BCLK{0/1}_D[N/P] are found in
Table 6-29. Overshoot/Undershoot and Ringback specifications for the DDR3 Reference
Clocks are specified by the DIMM.
6.12.5 Overshoot/Undershoot Tolerance
Overshoot (or undershoot) is the absolute value of the maximum voltage above or
below V
SS,
see Figure 6-25. The overshoot/undershoot specifications limit transitions
beyond V
VMSE
or V
SS
due to the fast signal edge rates. The processor can be damaged
by single and/or repeated overshoot or undershoot events on any input, output, or I/O
buffer if the charge is large enough (that is, if the over/undershoot is great enough).
Baseboard designs which meet signal integrity and timing requirements and which do
not exceed the maximum overshoot or undershoot limits listed in Table 6-29 will insure
reliable IO performance for the lifetime of the processor.
6.12.5.1 Overshoot/Undershoot Magnitude
Magnitude describes the maximum potential difference between a signal and its voltage
reference level. For the processor, both are referenced to V
SS
. It is important to note
that the overshoot and undershoot conditions are separate and their impact must be
determined independently.
The pulse magnitude and duration must be used to determine if the
overshoot/undershoot pulse is within specifications.
6.12.5.2 Overshoot/Undershoot Pulse Duration
Pulse duration describes the total amount of time that an overshoot/undershoot event
exceeds the overshoot/undershoot reference voltage. The total time could encompass
several oscillations above the reference voltage. Multiple overshoot/undershoot pulses
within a single overshoot/undershoot event may need to be measured to determine the
total pulse duration.
Note: Oscillations below the reference voltage cannot be subtracted from the total
overshoot/undershoot pulse duration.