Acer Intel Celeron G530 KC.53001.CDG Benutzerhandbuch
Produktcode
KC.53001.CDG
Intel
®
Celeron
®
Processor on 0.13 Micron Process in the 478-Pin Package Datasheet
45
System Bus Signal Quality Specifications
3.3
System Bus Signal Quality Specifications and
Measurement Guidelines
Measurement Guidelines
3.3.1
Overshoot/Undershoot Guidelines
Overshoot (or undershoot) is the absolute value of the maximum voltage above the nominal high
voltage (or below VSS) as shown in
voltage (or below VSS) as shown in
. The overshoot guideline limits transitions beyond
VCC or VSS because of the fast signal edge rates. The processor can be damaged by repeated
overshoot or undershoot events on any input, output, or I/O buffer if the charge is large enough
(i.e., 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.
overshoot or undershoot events on any input, output, or I/O buffer if the charge is large enough
(i.e., 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.
When performing simulations to determine impact of overshoot and undershoot, ESD diodes must
be properly characterized. ESD protection diodes do not act as voltage clamps and will not provide
overshoot or undershoot protection. ESD diodes modeled within Intel I/O buffer models do not
clamp undershoot or overshoot, and will yield correct simulation results. If other I/O buffer models
are being used to characterize the Celeron processor on 0.13 micron process system bus, care must
be taken to ensure that ESD models do not clamp extreme voltage levels. Intel I/O buffer models
also contain I/O capacitance characterization. Therefore, removing the ESD diodes from an I/O
buffer model will impact results and may yield excessive overshoot/undershoot.
be properly characterized. ESD protection diodes do not act as voltage clamps and will not provide
overshoot or undershoot protection. ESD diodes modeled within Intel I/O buffer models do not
clamp undershoot or overshoot, and will yield correct simulation results. If other I/O buffer models
are being used to characterize the Celeron processor on 0.13 micron process system bus, care must
be taken to ensure that ESD models do not clamp extreme voltage levels. Intel I/O buffer models
also contain I/O capacitance characterization. Therefore, removing the ESD diodes from an I/O
buffer model will impact results and may yield excessive overshoot/undershoot.
3.3.2
Overshoot/Undershoot Magnitude
Magnitude describes the maximum potential difference between a signal and its voltage reference
level. For the Celeron processor on 0.13 micron process, both are referenced to VSS. It is important
to note that overshoot and undershoot conditions are separate, and their impact must be determined
independently.
level. For the Celeron processor on 0.13 micron process, both are referenced to VSS. It is important
to note that overshoot and undershoot conditions are separate, and their impact must be determined
independently.
through
. These specifications must not be violated at any time regardless of
bus activity or system state. Within these specifications are threshold levels that define different
allowed pulse durations. Provided that the magnitude of the overshoot/undershoot is within the
absolute maximum specifications, the pulse magnitude, duration and activity factor must all be
used to determine whether the overshoot/undershoot pulse is within specifications.
allowed pulse durations. Provided that the magnitude of the overshoot/undershoot is within the
absolute maximum specifications, the pulse magnitude, duration and activity factor must all be
used to determine whether the overshoot/undershoot pulse is within specifications.
3.3.3
Overshoot/Undershoot Pulse Duration
Pulse duration describes the total time an overshoot/undershoot event exceeds the overshoot/
undershoot reference voltage (maximum overshoot = 1.800 V, maximum undershoot = -0.335 V).
The total time could encompass several oscillations above the reference voltage. Multiple
overshoot/undershoot pulses within a single overshoot/undershoot event may have to be measured
to determine the total pulse duration.
undershoot reference voltage (maximum overshoot = 1.800 V, maximum undershoot = -0.335 V).
The total time could encompass several oscillations above the reference voltage. Multiple
overshoot/undershoot pulses within a single overshoot/undershoot event may have to be measured
to determine the total pulse duration.
Note:
Oscillations below the reference voltage can not be subtracted from the total overshoot/undershoot
pulse duration.
pulse duration.