Sun Microsystems SME5224AUPA-400 - Manual (Page 41)

13
400 MHz CPU, 4.0 MB E-Cache
UltraSPARC ™ -II CPU Module
SME5224AUPA-400
Advanced Version
July 1999 Sun Microsystems, Inc
UPA Data Bus SPICE Model
A typical circuit for the UPA data bus and ECC signals is illustrated in Figure 4:.
Figure 4. Module System Loading: Example for UPA_DATA, UPA_ECC
3.1 nH
1.0 pF
Edge Connector
UDB-II Driver
Trace 1
0.5 nH
2 nH
50
Ω
via 0.6 pF
7 pF
Trace 2
XB1 BGA Package Loading
3.1 nH
Edge Connector
Trace 3
0.5 nH
2 nH
50
Ω
via 0.6 pF
7 pF
UDB-II of Second Module
Package Loading
Trace 4
Measure point for XB1
Measure point for CPU
Worst Case: Z
0
= 60
Ω
, T
P
= 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: Z
0
= 50
Ω
, T
P
= 160 ps/inch, Trace 1 Length = 2.2”, Trace 2 Length = 0.2”, Trace 3 Length
= 0.2”, Trace 4 Length = 2.2”
1.0 pF
1.0 pF 1.0 pF