Defining signal voltage in the PAD_INFO file
IC Verification & Signoff
How to define signal names and signal voltages for PERC LDL, P2P and CD checks.
When it comes to layout-based PERC checks like LDL, P2P, and CD, some foundries require that all signal net names (Power/Ground/Signal) are defined in the rule file and the voltage of each net is defined in a PAD_INFO file. The supported method to define the signal name and the voltage association is: VARIABLE SIGNAL NAME “<net_name>” VARIABLE “<net_name>” <voltage_value>
So, to have the correct setup for PERC checks, the net names must be defined in the rule file as a signal net with the VARIABLE SIGNAL NAME statement and the voltage information must be added in the PAD_ INFO file with the VARIABLE statement.
For example, if you have an IO net with 1.8 voltage, you need to define this net in the rule file as follows: VARIABLE SIGNAL NAME “IO”
And also, be sure to add the net voltage information in the PAD INFO file: VARIABLE “IO” 1.8