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

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

1.2.4. Troubleshooting ZEFF

When the decoupling mode is set to Auto, this may result in a ZEFF value that is too high. This can happen when the PCB parameters you entered result in an inefficient PDN, and the current to be decoupled by the PCB are unrealistically high.

With difficult PCB and current parameters, auto decoupling continues to add decoupling capacitors until it determines they have little effect. This results in hundreds of capacitors. You can achieve decoupling schemes with similar performance manually using far fewer capacitors.