Device-Specific Power Delivery Network (PDN) Tool 2.0 User Guide

ID 683293
Date 8/24/2021
Public
Document Table of Contents

1.2.2.1.7. VRM Impedance Section

Enter the VRM impedance values for the regulators. Use the pull-down menu to enter data for VRM Resistance and VRM Inductance.

There are three ways to change the voltage regulator module (VRM) parameters. Depending on what you select in the VRM Impedance pull-down menu, you can:

  • Select Custom, and set your desired Rvrm and Lvrm values.
  • Select Library, and get the suggested typical Rvrm and Lvrm values. This depends on the type of regulator (for example, switching, linear, or filter) you have selected.
  • Select Ignore, and Rvrm and Lvrm are not considered design parameters.
  • For switching regulators, you can choose a specific Intel® Enpirion® VRM (based on ordering code) directly in the pull-down menu.
    • Intel® Enpirion® models in the VRM library already include base required output capacitance for a base/default supported current. You must obtain the base/default output capacitors from the Intel® Enpirion® datasheet of the device you want to include into your PCB decoupling caps, if you select an Intel® Enpirion® device.
Figure 8. VRM Model

The R1 and L1 effect occurs at approximately 1 kHz to 50 kHz, which represents the regulator normal RL circuit without the closed loop.

The R2 and L2 effect occurs at 50 kHz to 300 kHz and represents the effect of the closed loop.

The Cout branch effect occurs between 300 kHz and 1 MHz.

The PDN tool can help you select the appropriate Intel® Enpirion® VRM module to use for each power supply in your system.