Ich2 layout checklist, Table 43. 8-bit hub interface, Table 44. ide interface – Intel CHIPSET 820E User Manual
Page 134: Table 45. usb
Intel
®
820E Chipset
R
134
Design
Guide
2.25.
ICH2 Layout Checklist
Table 43. 8-Bit Hub Interface
# Layout
Recommendations Yes
No
Comments
1
Board impedance must be 60 Ω ± 10%.
2
Traces must be routed 5 mils wide with 20 mils spacing.
3
In order to break out of the MCH and ICH2 package, the hub interface
signals can be routed 5 on 5. Signals must be separated to 5 on 20
within 300 mils of the package.
4
Max. trace length is 8 inches.
5
Data signals must be matched within ±0.1 inch of the HL_STB diff
pair.
6
Each strobe signal must be the same length.
7
HUBREF divider should be placed no more than 4 inches away from
MCH or ICH2. If so, then separate resistor divider must be placed
locally.
Table 44. IDE Interface
# Layout
Recommendations Yes
No
Comments
1
5 mils wide and 7 mil spaces
2
Max. trace length is 8 inches.
3
Shortest trace length must be 0.5 inch shorter than longest trace
length.
Table 45. USB
# Layout
Recommendations Yes
No
Comments
1
Characteristic impedance of individual signal lines P+, P- : Z
0
= 45
Ω
(90
Ω
differential)
2
Stack-up: 9 mils wide, 25 mil spacing between differential pairs
3 Trace
characteristics
•
Line delay = 160.2 ps
•
Capacitance = 3.5 pF
•
Inductance = 7.3 nH
•
Res at 20
o
C = 53.9 m
Ω
4 15
Ω
series resistor placed < 1 inch from ICH2.
5
47 pF parallel caps should be placed as close as possible to the ICH2.
6 15
k
Ω
± 5% pull-down resistors must be present on the connector side
of the series resistor.
7
Stub length due to 15 k
Ω
pull-downs should be as short as possible.