Dual Processor Power Requirements; Voltage Tolerance; Detailed Power Distribution Model For System With Vrm; Vrm 8.5 Board Power Distribution Model - Intel Pentium III Design Manual

To completely model the motherboard system, one must include the inductance and resistance which
exists in the cables, connectors, PCB planes, pins and body of components (such as resistors and
capacitors), processor socket and voltage regulator. A more detailed model showing these effects is
shown in Figure 5-3 below.
Figure 5-3. Detailed Power Distribution Model for System with VRM
Power Supply
psu
Both VRD and VRM solutions should be designed in conjunction with the recommended load model
referenced in Figure 5-4.
Figure 5-4. VRM 8.5 Board Power Distribution Model
VRM 8.5
5.3

Dual Processor Power Requirements

This section describes the issues related to supplying power to an Intel
512KB L2 Cache. For detailed electrical specifications, please refer to the Intel
with 512KB L2 Cache Datasheet.
5.3.1

Voltage Tolerance

®
Refer to the Intel Pentium
specifications. Failure to meet these specifications on the low-end tolerance results in transistors slowing
down and not meeting timing specifications. Not meeting the specifications on the high-end tolerance
can cause damage or reduce the life of the processor.
® ®
Intel Pentium III Processor with 512KB L2 Cache Dual Processor Platform Design Guide
Voltage Regulator Module
L
CABLE*
R S1
CABLE*
ESR
INPUT
ESL
INPUT
C
INPUT
L
CABLE*
R
CABLE*
+V (14)
SENSE
Lcon
V
Rcon
CORE
0.69nH
0.50mΩ
Rdecoup1
12/4mΩ
Ldecoup1
Cdecoup1
4*560µF
V
SS
-V (13)
SENSE
®
III Processor with 512KB L2 Cache Datasheet for voltage tolerance
L
VR
L
R BOARD
VR
ESR
BULK
S2
ESL
BULK
C
BULK
L
BOARD
R
+Vsense
1Ω
Lmb1 Lmb2
Rmb1 Rmb2
0.06mΩ 25.4pH 30.3pH
0.1mΩ
Rdecoup2
10/4mΩ
3.1/4nH Ldecoup2 1.1/4nH
Cdecoup2 4*22µF
R
-Vsen rtn
1Ω
Board Model
Processor
Equivalent model
L
*
SOCKET
*
R R
BOARD SOCKET
RHf
ESR
decouple
ESL LHf
decouple
C
decouple
L
*
SOCKET
*
R R
BOARD SOCKET
Rdecoup3
10/5mΩ
Processor
Ldecoup3
1.1/5nH
Cdecoup3
5*22µF
® ®
Pentium III Processor with
® ®
Pentium III Processor
CHf
5-3