Intel Itanium 2 Processor - Manual (Page 23)

Datasheet 23
Electrical Specifications
2.5 System Bus Signal Quality Specifications and
Measurement Guidelines
Overshoot (or undershoot) is the absolute value of the maximum voltage above the nominal
V
CTERM
voltage (or below GND), as shown in Table 2-3 . The overshoot/undershoot specifications
limit transitions beyond V
CTERM
or GND due to the fast signal edge rates. The processor can be
permanently damaged by repeated overshoot or undershoot events on any input, output, or I/O
buffer if the charge is large enough (that is, if the overshoot/undershoot is great enough).
Determining the impact of an overshoot/undershoot condition requires knowledge of the
magnitude, the pulse duration, and the activity factor (AF).
2.5.1 Overshoot/Undershoot Magnitude
Magnitude describes the maximum potential difference between a signal and its voltage reference
level. For the Itanium 2 processor, both are referenced to GND as shown in
Figure 2-3 . It is
important to note that overshoot and undershoot conditions are separate and their impact must be
determined independently. Overshoot/undershoot magnitude levels must observe the absolute
maximum specifications listed in
Table 2-13 through Table 2-21 . 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 duration. Provided that the magnitude of the
overshoot/undershoot is within the absolute maximum specifications (1.8 V for overshoot and
–0.60 V for undershoot), the pulse magnitude, duration and activity factor must all be used to
determine if the overshoot/undershoot pulse is within specifications.
V
in, SMBus
SMBus Buffer DC Input Voltage with
Respect to GND –0.1 6.0 V 4
V
in, AGTL+
AGTL+ Buffer DC Input Voltage with
Respect to GND –0.1 1.9 V 5, 6
V
CTERM
Any V
CTERM
Voltage with Respect to
GND
–0.1 1.9 V
3
V
in,TAP
TAP Buffer DC Input Voltage with
Respect to GND. –0.1 2.1 V 5
NOTES:
1. Storage temperature is temperature in which the processor can be stored for up to one year.
2. Shipping temperature is temperature in which the processor can be shipped for up to 24 hours.
3. See
Table 2-4 through Table 2-9 inclusive for operating voltages.
4. Parameters are from third party vendor specifications.
5. Maximum instantaneous voltage at receiver buffer input.
6. Specification includes V
in,AGTL+
and V
in,AGTL+ ASYNCHRONOUS
(AGTL+ asynchronous buffer DC input voltage with
respect to GND.
Table 2-12. Itanium
®
2 Processor Absolute Maximum Ratings (Sheet 2 of 2)
Symbol Parameter Minimum Maximum Unit Notes