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Platform Power Delivery Guidelines
R
266
Intel
®
855PM Chipset Platform Design Guide
Figure 146. Minimized Loop Inductance Example
Layer 1
Layer 2
Layer 3
Layer 4
GND
GND
4.5 mils nominal
48 mils nominal
BGA
BALL
BGA
BALL
BGA
S
PAD
Trace
connecting
Pad to Via
VIA
GND
Ball
PWR
Ball
Copper
Plane
Under BGA
Decoupling
Cap
PWR
Current Flow to Decoupling Cap
Table 83. Decoupling Requirements for the Intel 82801DBM ICH4-M
Pin Decoupling
Requirements
Decoupling Type (Pin type)
Decoupling Placement
VCC3_3
(6) 0.1 µF
Decoupling Cap (Vss)
Place near balls: A4, A1, H1, T1,
AC10, and AC18
VCCSUS3_3
(2) 0.1 µF
Decoupling Cap (Vss)
Place near balls: A22 and AC5
VCCLAN3_3
(2) 0.1 µF
Decoupling Cap (Vss)
Place near balls: E9 and F9
V_CPU_IO
(1) 0.1 µF
Decoupling Cap (Vcc)
Place near ball: AA23
VCC1_5
(2) 0.1 µF
Decoupling Cap (Vss)
Place near balls: K23 and C23
VCCSUS1_5
(2) 0.1 µF
Decoupling Cap (Vss)
Place near balls: A16 and AC1
VCCLAN1_5
(2) 0.1 µF
Decoupling Cap (Vss)
Place near balls: F6 and F7
V5REF
(1) 0.1 µF
Decoupling Cap (Vcc)
Place near ball: E7
V5REF_SUS
(1) 0.1 µF
Decoupling Cap (Vss)
Place near ball: A16
VCCRTC
(1) 0.1 µF
Decoupling Cap (Vcc)
Place near ball: AB5
VCCHI
(2) 0.1 µF
Decoupling Cap (Vss)
Place near balls: T23 and N23
VCCPLL
(1) 0.1 µF
(1) 0.01 µF
Decoupling Cap (Vcc)
Place near ball: C22
NOTES:
1.
Capacitors should be placed less than 100 mils from the package.
2.
ICH4-M balls listed in the “Decoupling Placement” guidelines column may not necessarily correlate to a VCC
power ball and may include signal balls from different interfaces.