Altera Device-Specific Power Delivery Network - Manual (Page 22)

1–18 Chapter 1: User Guide for the Device-Specific Power Delivery Network (PDN) Tool
Design PCB Decoupling Using the PDN Tool
Device-Specific Power Delivery Network (PDN) Tool User Guide September 2012 Altera Corporation
Design PCB Decoupling Using the PDN Tool
PCB decoupling keeps PDN Z
EFF
smaller than Z
TARGET
with the properly chosen PCB
capacitor combination up to the frequency where the capacitor on the package and die
take over the PDN decoupling. This section describes the procedure of designing PCB
decoupling using the PDN tool in different power rail configurations. This section
also provides design examples using the Stratix IV device PDN tool.
Pre-Layout Instructions
The PDN tool provides an accurate estimate of the number and types of capacitors
needed to design a robust power delivery network, regardless of where you are in the
design phase. However, the accuracy of the results depends highly on the user inputs
for the various parameters.
If you have finalized the board stack-up and have access to board database and layout
information, you can step through the tabs and enter the required information to
arrive at an accurate decoupling scheme.
In the pre-layout phase of the design cycle, when no specific information about the
board stack-up and board layout is known, you can follow the instructions in the
following sections to explore the solution space when finalizing key design
parameters such as stack-up, plane size, capacitor count, capacitor orientation, and so
on.