Voltage Regulator Module (VRM) 10.2L Design Guidelines
Voltage Regulator Module (VRM) 10.2L Design Guidelines 15
Output Voltage Requirements
2.7 Overshoot at Turn-On or Turn-Off - REQUIRED
The core VRM output voltage should remain within the load-line regulation band for the VID
setting, while the VRM is turning on or turning off, with no over or undershoot out of regulation.
No negative voltage below –100 mV may be present at the VRM output during turn-on or turn-off.
2.8 Output Filter Capacitance - REQUIRED
The output filter capacitance for VRM based designs will be located on the baseboard. The system
design must ensure that the output voltage of the VRM conforms to the load line of Figure 2-2 and
with the baseboard and processor loads. Table 2-2 shows the number of decoupling caps
recommended and other related specifications based on updated processor power requirements
supported by VRM 10.2L.
Figure 2-7 and Figure 2-8 provide a recommended example of a baseboard decoupling solution
and a processor load. The number of capacitors needed may change based on updated processor
power requirements. The values shown are for a four-phase 200 kHz to 800 kHz switching voltage
regulator design. The parasitic board values are extracted from a design using four layers of the
board with 2 ounces total of copper for Vcc and 2 ounces total of copper for ground. The type and
number of bulk decoupling required is dependent on the voltage regulator design and it is highly
recommended that the OEM work with the VRM supplier for an optimal decoupling solution for
their system and in accordance to the processor’s design requirements.
Table 2-2. Recommended Decoupling and Other Specifications for Supported Processors
Processor
560 µF
Alum-
Polymer
10 µF MLCC
Slew Rate
(di/dt)
A/µs
Thermal
Design
Current (A)
Max Icc (A)
64-bit Intel
®
Xeon™
processor MP with up to
8MB L3 cache
12 44 770 86 91
64-bit Intel
®
Xeon™
processor MP with 1MB
L2 cache
16 54 575 105 120
Figure 2-7. 64-bit Intel
®
Xeon™ Processor MP with up to 8MB L3 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