Intel® Celeron® Processor for PGA370 up to 1.40 GHz on 0.13 µ Process
that just meets the pulse duration for a specific magnitude where the AF < 1, means that there can
be NO other overshoot/undershoot events, even of lesser magnitude (note that if AF = 1, then the
event occurs at all times and no other events can occur).
Note: Activity factor for AGTL signals is referenced to system bus clock frequency.
Note: Activity factor for CMOS signals is referenced to PICCLK frequency.
3.2.5
Reading Overshoot/Undershoot Specification Tables
The overshoot/undershoot specification for the processor is not a simple single value. Instead,
many factors are needed to determine what the over/undershoot specification is. In addition to the
magnitude of the overshoot, the following parameters must also be known: the junction
temperature the processor will be operating at, the width of the overshoot (as measured above
TBD V) and the Activity Factor (AF). To determine the allowed overshoot for a particular
overshoot event, the following must be done:
1. Determine the signal group that particular signal falls into. If the signal is an AGTL signal
operating with a 100 MHz system bus, use Table 27 (100 MHz AGTL signal group). If the
signal is a CMOS signal, use Table 28 (33 MHz CMOS signal group).
2. Determine the maximum case temperature (Tcase) for the range of processors that the system
will support (65oC).
3. Determine the Magnitude of the overshoot (relative to VSS)
4. Determine the Activity Factor (how often does this overshoot occur?)
5. From the appropriate Specification table, read off the Maximum Pulse Duration (in ns)
allowed.
6. Compare the specified Maximum Pulse Duration to the signal being measured. If the Pulse
Duration measured is less than the Pulse Duration shown in the table, then the signal meets the
specifications.
The above procedure is similar for undershoots after the undershoot waveform has been converted
to look like an overshoot. Undershoot events must be analyzed separately from Overshoot events
as they are mutually exclusive.
Below is an example showing how the maximum pulse duration is determined for a given
waveform.
Table 26. Example Platform Information
Required Information
Maximum Platform Support
Notes
PSB Signal Group
Max Tcase
100 MHz AGTL
72 °C
Overshoot Magnitude
1.78 V
Measured Value
Measured overshoot occurs on
average every 20 clocks
Activity Factor (AF)
0.1
Given the above parameters, and using Table 27 (65oC/AF = 0.1 column) the maximum allowed
pulse duration is 7.5 ns. Since the measure pulse duration is 7.5 ns, this particular overshoot event
passes the overshoot specifications, although this doesn't guarantee that the combined overshoot/
undershoot events meet the specifications.
Datasheet
45
INTEL [ INTEL ]
