Intel Itanium 2 Processor manual Overshoot/Undershoot Magnitude

Electrical Specifications

Table 2-12. Itanium® 2 Processor Absolute Maximum Ratings (Sheet 2 of 2)

Symbol	Parameter	Minimum	Maximum	Unit	Notes
Vin, SMBus	SMBus Buffer DC Input Voltage with	–0.1	6.0	V	4
	Respect to GND
Vin, AGTL+	AGTL+ Buffer DC Input Voltage with	–0.1	1.9	V	5,	6
	Respect to GND
VCTERM	Any VCTERM Voltage with Respect to	–0.1	1.9	V	3
	GND
Vin,TAP	TAP Buffer DC Input Voltage with	–0.1	2.1	V	5
	Respect to GND.
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 2-4through Table 2-9inclusive for operating voltages.

4.Parameters are from third party vendor specifications.

5.Maximum instantaneous voltage at receiver buffer input.

6.Specification includes Vin,AGTL+ and Vin,AGTL+ ASYNCHRONOUS (AGTL+ asynchronous buffer DC input voltage with respect to GND.

2.5System Bus Signal Quality Specifications and Measurement Guidelines

Overshoot (or undershoot) is the absolute value of the maximum voltage above the nominal

VCTERM voltage (or below GND), as shown in Table 2-3. The overshoot/undershoot specifications limit transitions beyond VCTERM 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).

2.5.1Overshoot/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 2-13through 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.

Datasheet 23