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Platform Design Checklist
R
302
Intel
®
855PM Chipset Platform Design Guide
14.6.6.
MCH Reference Voltage
MCH – Reference Voltage
Pin Name
System
Pull up/Pull down
Notes
9
AGPREF
Voltage divider
1 k
± 1%
(top & bottom)
HI_REF
Voltage divider
100
- 150
± 1%
(top & bottom)
See Notes
HIVREF(ICH4-M signal), HI_VSWING (ICH4-M signal),
and HI_REF(MCH signal) may share a common hub
interface reference voltage divider if the divider is
located within 3” from both the MCH and ICH4-M.
See Figure 157 and Section 8.4 for more details.
For each of the 3 signals, a locally generated hub
interface reference voltage divider must be used if the
common reference voltage divider is located more than
3” away from the component.
See Figure 158 and Section 8.4 for more details.
HVREF[4:0]
49.9
± 1%
(top)
100
± 1%
(bottom)
Place R1 close to HVREF4 (ballout AB16) and R2
close to HVREF1 (ballout P8).
See Figure 155.
R1a = 49.9
± 1%
R2a = 100
± 1%
C1 = 200 pF C2 = 200 pF C3 = 1 µF
See Section 4.1.7 for routing requirements.