Altera Device-Specific Power Delivery Network - Manual (Page 12)

1. Select the Plane_Cap tab in the PDN tool 2.0.
2. Set the parameters to match your system, and notice that the Total planar capacitance and Total
sheet resistance values are updated automatically .
3. In the System_Decap tab, select the Custom option for each group where a custom plane is required.
4. Enter the calculated Ctotal and Rtotal values into the Plane section of the System_Decap tab.
Setting the Plane table to Calculate or Ignore causes the System_Decap tab to use the same global
settings for all rail groups.
Spreading Section
In the Spreading table, you can set the tool to one of the following options:
• Ignore
• Low
• Medium
• High
• Custom
For a fully customized workflow in which each rail group can have different settings:
1. Select the Library tab in the PDN tool 2.0.
2. Set the parameters in the Spreading R and L table to match your system.
3. Examine the range of spreading R and L values to determine if you need a custom R and L. If a custom
R and L is warranted, select Custom in the System_Decap tab and set the R and L values directly.
Setting the Spreading table to Low, Medium, High, or Ignore causes the System_Decap tab to use the
same global settings for all rail groups.
F
EFFECTIVE
Section
You can set Feffective to Calculate or Override. Select the Calculate option to use the Altera
recommended cut off frequency based on package and die parasitics.
Decoupling Section
You can set Decoupling to Manual or Auto. If you select the Auto option, any change you make to the
system is automatically reflected in the decoupling solution. You can also view the impedance chart per
rail group or VRM.
Selecting the Manual option allows you to:
• Lock in calculated decoupling solutions from being further optimized by any changes made to the
System_Decap tab.
• Add or remove the number and type of decoupling capacitors in the Results Summary section. You
can see its immediate impact on the impedance profile curve.
Results Summary Section
You can find the list of the number and type of capacitors used for each group, and the summary of all the
capacitors used. The values in each column indicate the number of capacitors needed of each value for
each rail.
12 Spreading Section
UG-01157
2015.03.06
Altera Corporation Device-Specific Power Delivery Network (PDN) Tool 2.0 User Guide
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