Voltage Regulator Module (VRM) and Enterprise Voltage Regulator-Down (EVRD) 10.0 Design Guidelines

VRM and EVRD 10.0 Design Guidelines

4 Input Voltage and Current

4.1 Input Voltages EXPECTED

The power source for the VRM/EVRD is 12 V +5/–8%. This voltage is supplied by a separate

power supply. For input voltages outside the normal operating range, the VRM/EVRD should

either operate properly or shut down.

4.2 Load Transient Effects on Input Current EXPECTED

The design of the VRM/EVRD, including the input power delivery filter must ensure that the

maximum slew rate of the input current does not exceed 0.5 A/µs, or as specified by the separate

power supply.

Note: In the case of a VRM design, the input power delivery filter may be located either on the VRM or

on the baseboard. The decision for the placement of the filter will need to be coordinated between

the baseboard and VRM designers.

It is recommended that the bulk input decoupling be placed on the baseboard by the VRM input

connector and high frequency decoupling on the VRM module. The expected baseboard

decoupling should be between 1000 µF to 2240 µF depending on the VRM design and system

power supply.