Intel III Xeon 550 MHz 80525KY5501M User Manual
Product codes
80525KY5501M
Pentium
®
III Xeon™ Processor at 500 and 550 MHz
Datasheet
35
3.3
Non-AGTL+ Signal Quality Specifications
There are three signal quality parameters defined for non-AGTL+ signals: overshoot/undershoot,
ringback, and settling limit. All three signal quality parameters are shown in
ringback, and settling limit. All three signal quality parameters are shown in
for the non-
AGTL+ signal group at the processor core pads.
3.3.1
2.5 V Tolerant Buffer Overshoot/Undershoot Guidelines
The overshoot/undershoot guideline limits transitions beyond V
CC
or V
SS
due to fast signal edge
for non-AGTL+ signals.) The processor can be damaged by repeated
overshoot or undershoot events on 2. 5V tolerant buffers if great enough. The overshoot/undershoot
guideline is shown in
guideline is shown in
3.3.2
2.5 V Tolerant Buffer Ringback Specification
The ringback specification is the voltage at a receiving pin that a signal rings back to after
achieving its maximum absolute value. (See
achieving its maximum absolute value. (See
for an illustration of ringback.) Excessive
ringback can cause false signal detection or extend the propagation delay. Violations of the signal
ringback specification are not allowed for 2 .5V tolerant signals.
ringback specification are not allowed for 2 .5V tolerant signals.
simulations at the processor core.
Table 20. AGTL+ Overshoot/Undershoot Guidelines at the Processor Core
Guideline
Transition
Signal Must Maintain
Unit
Figure
Overshoot
0
→
1
< 2.7
V
Undershoot
1
→
0
> -0.7
V
Figure 15. Non-AGTL+ Overshoot/Undershoot, Settling Limit, and Ringback
U ndershoot
Ov ershoot
Settli ng L i mi t
Settli ng L i mi t
Ri si ng-Edge
Ri ngback
Ri ngback
Fal l ing-Edge
Ri ngback
Ri ngback
V
L O
V
SS
T ime
V =
H I
V
CC
2.5
V oltage
Table 21. 2.5 V Tolerant Signal Overshoot/Undershoot Guidelines at the Processor Core
Guideline
Transition
Signal Must Maintain
Unit
Figure
Overshoot
0
→
1
< 3.2
V
Undershoot
1
→
0
> -0.3
V