Intel® 820E Chipset

R

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- : Z0 = 45

 

 

 

 

(90 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 20o C = 53.9 m

 

 

 

4

15 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± 5% pull-down resistors must be present on the connector side

 

 

 

 

of the series resistor.

 

 

 

 

 

 

 

 

7

Stub length due to 15 kpull-downs should be as short as possible.

 

 

 

 

 

 

 

 

134

Design Guide

Page 134
Image 134
Intel 820E manual ICH2 Layout Checklist, Bit Hub Interface, IDE Interface, Usb, Layout Recommendations Yes Comments