124
Hardware Design Guide
IXP28XX Network Processor
PCI
6.5
Package Trace Lengths for PCI Signals
Table 46
provides package trace lengths for PCI signals.
Note:
It is typically not required to account for the package trace length for PCI interface signals.
The flight time on the package substrate is 154ps/in which differs from the flight delay of standard
FR4, typical 180ps/in. As a result the package routing lengths in
Table 46
must be adjusted to
compensate for the difference in flight delay between the package and the PCB. For example
PCI_ACK64_L has a package length of 0.593 in, and the target PCB has a flight delay of 180ps/in.
In order to adjust the package length to match the PCB flight delay this length must be multiplied
by the ratio of 154/180 or the difference between the package and PCB flight delays. Therefore the
trace package routing length that must be accounted for on the PCB is 0.593*(154/180) or 0.507 in.
Note:
If the flight delay of the target PCB is not 180 ps/in then the ratio, (154/180), must be modified
accordingly, i.e., the denominator would be changed to reflect the actual flight delay.
Table 46.
Package Trace Lengths for PCI Signals (Sheet 1 of 2)
Signal
Metric
Units
(mm)
English
Units
(in)
Signal
Metric
Units
(mm)
English
Units
(in)
Signal
Metric
Units
(mm)
English
Units
(in)
PCI_ACK64_L
15.052
0.593
PCI_AD[38]
8.43
0.332
PCI_CBE_L[1]
3.597
0.142
PCI_AD[0]
6.118
0.241
PCI_AD[39]
15.183
0.598
PCI_CBE_L[2]
1.571
0.062
PCI_AD[1]
7.934
0.312
PCI_AD[4]
4.626
0.182
PCI_CBE_L[3]
9.587
0.377
PCI_AD[10]
11.996
0.472
PCI_AD[40]
5.386
0.212
PCI_CBE_L[4]
13.866
0.546
PCI_AD[11]
16.187
0.637
PCI_AD[41]
14.329
0.564
PCI_CBE_L[5]
3.349
0.132
PCI_AD[12]
2.379
0.094
PCI_AD[42]
9.768
0.385
PCI_CBE_L[6]
10.543
0.415
PCI_AD[13]
10.843
0.427
PCI_AD[43]
10.39
0.409
PCI_CBE_L[7]
6.818
0.268
PCI_AD[14]
13.881
0.546
PCI_AD[44]
4.96
0.195
PCI_CLK
5.22
0.206
PCI_AD[15]
13.628
0.537
PCI_AD[45]
4.537
0.179
PCI_DEVSEL_L
8.571
0.337
PCI_AD[16]
8.055
0.317
PCI_AD[46]
2.088
0.082
PCI_FRAME_L
4.673
0.184
PCI_AD[17]
11.044
0.435
PCI_AD[47]
12.445
0.490
PCI_GNT_L[0]
14.405
0.567
PCI_AD[18]
3.802
0.150
PCI_AD[48]
5.838
0.230
PCI_GNT_L[1]
13.908
0.548
PCI_AD[19]
7.593
0.299
PCI_AD[49]
11.942
0.470
PCI_IDSEL
11.147
0.439
PCI_AD[2]
14.995
0.590
PCI_AD[5]
9.05
0.356
PCI_INTA_L
12.348
0.486
PCI_AD[20]
12.79
0.504
PCI_AD[50]
10.852
0.427
PCI_INTB_L
7.397
0.291
PCI_AD[21]
10.251
0.404
PCI_AD[51]
10.741
0.423
PCI_IRDY_L
5.826
0.229
PCI_AD[22]
10.299
0.405
PCI_AD[52]
1.893
0.075
PCI_M66EN
1.72
0.068
PCI_AD[23]
5.299
0.209
PCI_AD[53]
11.913
0.469
PCI_PAR
13.373
0.526
PCI_AD[24]
1.845
0.073
PCI_AD[54]
5.843
0.230
PCI_PAR64
5.838
0.230
PCI_AD[25]
17.686
0.696
PCI_AD[55]
7.053
0.278
PCI_PERR_L
2.9
0.114
PCI_AD[26]
7.434
0.293
PCI_AD[56]
7.908
0.311
PCI_REQ_L[0]
3.644
0.143
PCI_AD[27]
2.48
0.098
PCI_AD[57]
10.645
0.419
PCI_REQ_L[1]
9.697
0.382
PCI_AD[28]
12.666
0.499
PCI_AD[58]
2.518
0.099
PCI_REQ64_L
1.72
0.068
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