Pentium® III Processor for the PGA370 Socket at 500 MHz to 866 MHz
3.3.6
Determining if a System meets the Overshoot/Undershoot
Specifications
The overshoot/undershoot specifications listed in the following tables specify the allowable
overshoot/undershoot for a single overshoot/undershoot event. However most systems will have
multiple overshoot and/or undershoot events that each have their own set of parameters (duration,
AF and magnitude). While each overshoot on its own may meet the overshoot specification, when
you add the total impact of all overshoot events, the system may fail. A guideline to ensure a
system passes the overshoot and undershoot specifications is shown below. It is important to meet
these guidelines; otherwise, contact your Intrel field representative.
1. Insure no signal (CMOS or AGTL+) ever exceed the 1.635V
OR
2. If only one overshoot/undershoot event magnitude occurs, ensure it meets the over/undershoot
specifications in the following tables
OR
3. If multiple overshoots and/or multiple undershoots occur, measure the worst case pulse
duration for each magnitude and compare the results against the AF = 1 specifications. If all of
these worst case overshoot or undershoot events meet the specifications (measured time <
specifications) in the table (where AF=1), then the system passes.
The following notes apply to Table 20 through Table 22.
NOTES:
1. Overshoot/Undershoot Magnitude = 2.18V is an Absolute value and should never be exceeded
2. Overshoot is measured relative to VSS.
3. Undershoot is measured relative to VTT
4. Overshoot/Undershoot Pulse Duration is measured relative to 1.635V.
5. Rinbacks below VTT can not be subtracted from Overshoots/Undershoots
6. Lesser Undershoot does not allocate longer or larger Overshoot
7. OEM's are encouraged to follow Intel provided layout guidelines. Consult the layout guidelines
provided in the specific platform design guide.
8. All values specified by design characterization
Table 20. 100 MHz AGTL+ Signal Group Overshoot/Undershoot Tolerance at Processor Pins1,2
Maximum Pulse Duration at Tj = 80 °C
Maximum Pulse Duration at Tj = 85 °C
Overshoot/
Undershoot
Magnitude
(ns)
(ns)
AF = 0.01
AF = 0.1
AF = 1
AF = 0.01
AF = 0.1
AF = 1
2.18 V
2.13 V
2.08 V
2.03 V
1.98 V
1.93 V
1.88 V
20
20
20
20
20
20
20
2.53
4.93
9.1
16.6
20
0.25
0.49
0.91
1.67
3.0
18.6
20
1.86
3.2
6.1
11.4
20
0.18
0.32
0.6
1.1
2
20
20
20
20
5.5
20
20
6.6
20
20
10
20
20
1. BCLK period is 10 ns.
2. Measurements taken at the processor socket pins on the solder-side of the motherboard.
Datasheet
39
INTEL [ INTEL ]
