Voltage Regulator Module (VRM) and Enterprise Voltage Regulator-Down (EVRD) 10.2 Design Guidelines
Output Voltage Requirements
16 Voltage Regulator Module (VRM) and Enterprise Voltage
Regulator-Down (EVRD) 10.2 Design Guidelines
This VRM/EVRD10.2 design incorporates sixteen 560 µF Aluminum-polymer bulk capacitors and
fifty-four 10 µF ceramic high-frequency capacitors per processor (Table 2-3). Eight of the fifty-
four 10 µF capacitors should be placed in the cavity of the processor socket. The remaining forty-
six capacitors should be split evenly such that half are on one side of the processor socket and half
are on the other side as close to the processor socket as the keep-out zones allow. If backside
passive components were allowed in the design, it would be beneficial to place the forty-six
capacitors under the processor socket on the backside of the baseboard. Eight of the sixteen 560 µF
capacitors should be placed on one side of the processor socket and the other eight on the opposite
side as close to the processor socket as the keep-out zones allow.
Note: The amount of bulk decoupling needed is dependent on the voltage regulator design. Some
multiphase buck regulators may have a higher switching frequency that would require a different
output decoupling solution to meet the processor load line requirements than described in this
document.
Figure 2-7. 64-bit Intel
®
Xeon™ Processor MP with up to 8MB L3 Cache Load Model
Figure 2-8. 64-bit Intel
®
Xeon™ Processor MP with up to 1MB L2 Cache Load Model
Socket and
Package Pins
0.34m
35pH
PWL
80 uF6720 uF
VR
1.25m
150 pH
0.58m
333 pH
8 X 10 uF
1206 MLCC
12 X 560 uF
Aluminum-Polymer
0.5m
30 pH
360 uF
0.28m
33 pH
36 X 10 uF
1206 MLCC
Baseboard
Die
Sense
Point
mPGA 604 Socket and
Package Pins
0.34m
7 pH
80 uF8960 uF
VRM
1.25m
138 pH
0.44m
250 pH
8 X 10 uF
1206
16 X 560 uF
Aluminum-Polymer
0.25m
10 pH
460 uF
0.22m
24 pH
46 X 10 uF
1206
Motherboard
PWL
VR
Sense
Point
Table 2-3. VRM 10.2 Decoupling Capacitor Recommendations
Quantity Value Tolerance
Temperature
Coefficient
ESR
(mΩ)
ESL
(nH)
Notes
16 560 µF Al-Polymer ±20% N/A 7 4
46 10 µF Ceramic ±20% X5R or X6S 10 1.1
8 10 µF Ceramic ±20% X6S 10 1.1 1