450NX Datasheet, PDF (148/248 Pages) Intel Corporation – Intel 450NX PCIset

12. Electrical Characteristics
12.7.2 Intel^® 450NX PCIset Undershoot Specification
The undershoot specification for the Intel 450NX PCIset components (and Pentium II Xeon
processor) is as follows:
The Pentium II Xeon processor bus signals AERR#, BERR#, BINIT#, BNR#, HIT#, and HITM#
(only) are capable of sinking an 85mA current pulse at a 2.4% average time duty cycle. This is
equivalent to -1.7V applied to a 20Ω source in series with the device pin for 5.38 ns at
100 MHz with a utilization of 5%.
This test covers the AC operating conditions only
0.5ns (max)
+1.7 V
Voltage source
waveform
-1.7 V
7.5 ns (max)
3.4V, p-to-p (max) _R
DUT
V
Undershoot Test Waveform
Voltage Source Impedance
R = 20 ohms
Average duty cycle of 2.4%.
Figure 12-14: Undershoot Test Setup
12.7.3 Skew Requirements
The skew requirement for XpRST# versus XpRSTFB#, and XpCLK versus XpCLKFB is +/-
125ps.
The electrical length (delay) from the XpCLK# signal pin on the MIOC to the clock input of the
PXB must match the delay to the XpCLKFB# pin on the MIOC by that amount. The same is
true with XpRST# and XpRSTFB#.
12-24
Intel® 450NX PCIset