Intel Xeon E5440 BX80574E5440 Hoja De Datos
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BX80574E5440
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Quad-Core Intel® Xeon® Processor 5400 Series Electrical Specifications
2
Quad-Core Intel® Xeon®
Processor 5400 Series Electrical
Specifications
2.1
Front Side Bus and GTLREF
Most Quad-Core Intel® Xeon® Processor 5400 Series FSB signals use Assisted
Gunning Transceiver Logic (AGTL+) signaling technology. This technology provides
improved noise margins and reduced ringing through low voltage swings and controlled
edge rates. AGTL+ buffers are open-drain and require pull-up resistors to provide the
high logic level and termination. AGTL+ output buffers differ from GTL+ buffers with
the addition of an active PMOS pull-up transistor to “assist” the pull-up resistors during
the first clock of a low-to-high voltage transition. Platforms implement a termination
voltage level for AGTL+ signals defined as V
Gunning Transceiver Logic (AGTL+) signaling technology. This technology provides
improved noise margins and reduced ringing through low voltage swings and controlled
edge rates. AGTL+ buffers are open-drain and require pull-up resistors to provide the
high logic level and termination. AGTL+ output buffers differ from GTL+ buffers with
the addition of an active PMOS pull-up transistor to “assist” the pull-up resistors during
the first clock of a low-to-high voltage transition. Platforms implement a termination
voltage level for AGTL+ signals defined as V
TT
. Because platforms implement separate
power planes for each processor (and chipset), separate V
CC
and V
TT
supplies are
necessary. This configuration allows for improved noise tolerance as processor
frequency increases. Speed enhancements to data and address buses have made
signal integrity considerations and platform design methods even more critical than
with previous processor families. Design guidelines for the processor FSB are detailed
in the appropriate platform design guidelines (refer to
frequency increases. Speed enhancements to data and address buses have made
signal integrity considerations and platform design methods even more critical than
with previous processor families. Design guidelines for the processor FSB are detailed
in the appropriate platform design guidelines (refer to
The AGTL+ inputs require reference voltages (GTLREF_DATA_MID, GTLREF_DATA_END,
GTLREF_ADD_MID, and GTLREF_ADD_END) which are used by the receivers to
determine if a signal is a logical 0 or a logical 1. GTLREF_DATA_MID and
GTLREF_DATA_END is used for the 4X front side bus signaling group and
GTLREF_ADD_MID and GTLREF_ADD_END is used for the 2X and common clock front
side bus signaling groups. GTLREF_DATA_MID, GTLREF_DATA_END,
GTLREF_ADD_MID, and GTLREF_ADD_END must be generated on the baseboard (See
GTLREF_ADD_MID, and GTLREF_ADD_END) which are used by the receivers to
determine if a signal is a logical 0 or a logical 1. GTLREF_DATA_MID and
GTLREF_DATA_END is used for the 4X front side bus signaling group and
GTLREF_ADD_MID and GTLREF_ADD_END is used for the 2X and common clock front
side bus signaling groups. GTLREF_DATA_MID, GTLREF_DATA_END,
GTLREF_ADD_MID, and GTLREF_ADD_END must be generated on the baseboard (See
for GTLREF_DATA_MID, GTLREF_DATA_END, GTLREF_ADD_MID, and
GTLREF_ADD_END specifications). Refer to the applicable platform design guidelines
for details. Termination resistors (R
for details. Termination resistors (R
TT
) for AGTL+ signals are provided on the processor
silicon and are terminated to V
TT
. The on-die termination resistors are always enabled
on the Quad-Core Intel® Xeon® Processor 5400 Series to control reflections on the
transmission line. Intel chipsets also provide on-die termination, thus eliminating the
need to terminate the bus on the baseboard for most AGTL+ signals.
transmission line. Intel chipsets also provide on-die termination, thus eliminating the
need to terminate the bus on the baseboard for most AGTL+ signals.
Some FSB signals do not include on-die termination (R
TT
) and must be terminated on
for details regarding these signals.
The AGTL+ bus depends on incident wave switching. Therefore, timing calculations for
AGTL+ signals are based on flight time as opposed to capacitive deratings. Analog
signal simulation of the FSB, including trace lengths, is highly recommended when
designing a system. Contact your Intel Field Representative to obtain the Quad-Core
Intel® Xeon® Processor 5400 Series signal integrity models, which includes buffer and
package models.
AGTL+ signals are based on flight time as opposed to capacitive deratings. Analog
signal simulation of the FSB, including trace lengths, is highly recommended when
designing a system. Contact your Intel Field Representative to obtain the Quad-Core
Intel® Xeon® Processor 5400 Series signal integrity models, which includes buffer and
package models.