Voltage Regulator Module (VRM) 10.2L Design Guidelines

Output Voltage Requirements

16 Voltage Regulator Module (VRM) 10.2L Design Guidelines

This design incorporates 560 µF Aluminum-polymer bulk capacitors and 10 µF ceramic high-

frequency capacitors. Eight of the 10 µF capacitors should be placed in the cavity of the processor

socket. The remaining 10 µF 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 keepout zones

allow. If backside passive components were allowed in the design, it would be beneficial to place

the remaining 10 µF capacitors under the processor socket on the backside of the baseboard. Half

of the 560-µF capacitors should be placed on one side of the processor socket and half on the other

side as close to the processor socket as the keepout 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.

NOTE:

1. Only the decoupling caps inside the socket cavity need to have the temperature coefficient of “X6S”.

In Figure 2-7, the capacitance labeled “mPGA604 Socket and Package Pins” is supplied by Intel

Corporation and is beyond the control of the system designer.

It is recommended that the system designer work with the VRM supplier to ensure proper

implementation of the VRM converter.

2.9 Shut-Down Response - REQUIRED

Once the VRM is operating after power-up, if either the Output Enable signal is deasserted or VID

[5:0] = X11111, the VRM should turn off its output (the output should go to high impedance)

within 500 ms.

Figure 2-8. 64-bit Intel

Xeon™ Processor MP with up to 1MB L2 Cache Load Model

Table 2-3. VRM 10.2L Decoupling Capacitor Recommendations

Value Tolerance

Temperature

Coefficient

ESR

(mΩ)

ESL

(nH)

Note

560 µF Al-Polymer ±20% NA 7 4

10 µF Ceramic ±20% X5R or X6S 10 1.2 1