Advanced Version | |
400 MHz CPU, 4.0 MB |
UPA Data Bus SPICE Model
A typical circuit for the UPA data bus and ECC signals is illustrated in Figure 4:.
Edge Connector
Trace 1 | 3.1 nH |
Trace 2 |
1.0 pF 1.0 pF
via 0.6 pF
7 pF
0.5 nH 50 Ω 2 nH
Edge Connector
3.1 nH
Trace 3
1.0 pF 1.0 pF
Measure point for XB1
Trace 4
via 0.6 pF
0.5 nH 50 Ω
XB1 BGA Package Loading
Measure point for CPU
7 pF
2 nH
Package Loading
Worst Case: Z0 = 60Ω, TP = 180 ps/inch, Trace 1 Length = 4.4”, Trace 2 Length = 0.6”, Trace 3 Length = 1.2”, Trace 4 Length = 4.4”
Best Case: Z0 = 50Ω, TP = 160 ps/inch, Trace 1 Length = 2.2”, Trace 2 Length = 0.2”, Trace 3 Length = 0.2”, Trace 4 Length = 2.2”
Figure 4. Module System Loading: Example for UPA_DATA, UPA_ECC
July 1999 | Sun Microsystems, Inc | 13 |