Техническая Спецификация для Intel Xeon 5150 2.66 GHz 124695
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124695
Dual-Core Intel
®
Xeon
®
Processor 5100 Series Datasheet
17
Electrical Specifications
2
Electrical Specifications
2.1
Front Side Bus and GTLREF
Most Dual-Core Intel
®
Xeon
®
Processor 5100 Series FSB signals uses Assisted Gunning
Transceiver Logic (AGTL+) signaling technology. This technology provides improved
noise margins and reduced ringing through low voltage swings and controlled edge
rates.
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
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 and GTLREF_ADD) which
are used by the receivers to determine if a signal is a logical 0 or a logical 1.
GTLREF_DATA is used for the 4X front side bus signaling group and GTLREF_ADD is
used for the 2X and common clock front side bus signaling groups. Both GTLREF_DATA
and GTLREF_ADD must be generated on the baseboard. Refer to the applicable
platform design guidelines for details. Termination resistors (R
are used by the receivers to determine if a signal is a logical 0 or a logical 1.
GTLREF_DATA is used for the 4X front side bus signaling group and GTLREF_ADD is
used for the 2X and common clock front side bus signaling groups. Both GTLREF_DATA
and GTLREF_ADD must be generated on the baseboard. Refer to the applicable
platform design guidelines 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 Dual-Core Intel
®
Xeon
®
Processor 5100 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.
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 processor
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 processor
signal integrity models, which includes buffer and package models.
2.2
Power and Ground Lands
For clean on-chip processor core power distribution, the processor has 223 V
CC
(power)
and 273 V
SS
(ground) inputs. All Vcc lands must be connected to the processor power
plane, while all V
SS
lands must be connected to the system ground plane. The
processor V
CC
lands must be supplied with the voltage determined by the processor
Voltage IDentification (VID) signals. See
for VID definitions.
Twenty two lands are specified as V
TT
, which provide termination for the FSB and
provides power to the I/O buffers. The platform must implement a separate supply for
these lands which meets the V
these lands which meets the V
TT
specifications outlined in
.