Intel CM8062101038606, E5-4600, E5-2600 Intel QuickPath Interconnect Signal Quality Specifications

7.9.3Intel QuickPath Interconnect Signal Quality Specifications

Signal Quality specifications for Differential Intel® QuickPath Interconnect Signals are included as part of the Intel QuickPath Interconnect signal quality specifications. Various scenarios have been simulated to generate a set of layout guidelines which are available in the appropriate Platform Design Guide (PDG).

7.9.4Input Reference Clock Signal Quality Specifications

Overshoot/Undershoot and Ringback specifications for BCLK{0/1}_D[N/P] are found in Table 7-24. Overshoot/Undershoot and Ringback specifications for the DDR3 Reference Clocks are specified by the DIMM.

7.9.5Overshoot/Undershoot Tolerance

Overshoot (or undershoot) is the absolute value of the maximum voltage above or below VSS, see Figure 7-11. The overshoot/undershoot specifications limit transitions beyond VCCD or VSS 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). Determining the impact of an overshoot/undershoot condition requires knowledge of the magnitude, the pulse direction, and the activity factor (AF). Permanent damage to the processor is the likely result of excessive overshoot/undershoot.

Baseboard designs which meet signal integrity and timing requirements and which do not exceed the maximum overshoot or undershoot limits listed in Table 7-24will insure reliable IO performance for the lifetime of the processor.

Table 7-24. Processor I/O Overshoot/Undershoot Specifications

Signal Group	Minimum	Maximum	Overshoot	Undershoot	Notes
	Undershoot	Overshoot	Duration	Duration
Intel QuickPath Interconnect	-0.2 * VTT	1.2 * VTT	39 ps	15 ps	1,2
DDR3	-0.2 * VCCD	1.2 * VCCD	0.25*TCH	0.1*TCH	1,2,3
System Reference Clock (BCLK{0/1})	-0.3V	1.15V	N/A	N/A	1,2
PWRGOOD Signal	-0.420V	VTT + 0.28	N/A	N/A	4

Notes:

1.These specifications are measured at the processor pad.

2.Refer to Figure 7-11for description of allowable Overshoot/Undershoot magnitude and duration.

3.TCH is the minimum high pulse width duration.

4.For PWRGOOD DC specifications see Table 7-22.

7.9.5.1Overshoot/Undershoot Magnitude

Overshoot/Undershoot magnitude describes the maximum potential difference between a signal and its voltage reference level. For the processor, both overshoot and undershoot magnitude are referenced to VSS. 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, and activity factor must be used to determine if the overshoot/undershoot pulse is within specifications.

184	Intel® Xeon® Processor E5-1600/E5-2600/E5-4600 Product Families
	Datasheet Volume One