Platform Design Checklist
R
Intel
®
855PM Chipset Platform Design Guide
301
14.6.4.
Decoupling Recommendations (MCH)
MCH– Decoupling Recommendations
1
Pin
Name Configuration F
Qty
Notes
9
SMRCOMP
Tie to Vcc1_25[DDR_Vtt]
0.1 µF
1
Decoupling capacitor must be connected to
the power-side of the RCOMP resistor.
Vcc1_8
Tie to Vcc1_8
0.1 µF
2
Two 0.1 µF capacitors are recommended
for Vcc1_8 decoupling. All values are
preliminary.
See Section 8.5 for details
VccSus2_5
Tie to VccSus2_5
0.1 µF
15
Place within 150 mils of MCH package.
See Section 11.5.1.1
VCC-MCH
Tie to VCC_MCH
150 µF
2.2 µF
220 nF
47 nF
22 nF
15 nF
10 nF
2
1
1
1
1
1
1
See Section 5.9.5for details.
VCCGA, VCCHA
Tie to Vcc1_8
10 µF
10 nF
1
1
VCCGA and VCCHA can both share a 10
µF and 10nF decoupling capacitor.
VCCP
Tie to VCCP
10 µF
0.1 µF
1
8
Polymer covered tantalum. Place next to
the MCH.
0603 MLCC, >= X7R. Place next to the
MCH.
14.6.5.
Memory Decoupling Recommendation
Memory Decoupling Recommendations
1
Pin
Name Configuration F
Qty
Notes
9
Vcc1_25[DDR_Vtt]
See Notes
0.1 µF
See Notes
In S3, Vcc1_25[DDR_Vtt] (DDR channel
termination voltage) can be turned OFF.
Place one 0.1 µF close to every 2 pull up
resistors terminated to Vcc1_25[DDR_Vtt].
See Section 11.7.4 for details.
VccSus2_5
0.1 µF
9
Place capacitors between the SO-DIMMs .
See Section 11.5.1.2 for details.