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Other CAD Tools >> Physical Verification, Extraction and Analysis >> Several "ground" and "Vdd" connections
https://designers-guide.org/forum/YaBB.pl?num=1192547136

Message started by DoYouLinux on Oct 16^th, 2007, 8:05am

Title: Several "ground" and "Vdd" connections
Post by DoYouLinux on Oct 16^th, 2007, 8:05am

Hi all,

I just forgot a thing to ask. In my layout, I have to "Gnd" connections for ground and two "Vdd" connections for a supply voltage. Actually, each of them will be independently connected to each pad, and then will be tied together to the supply and to the ground plane outside the chip (on a PCB). However, in my schematic, I have only one "Vdd" pin and one "Gnd" pin.

When I ran LVS, do I need to set any parameter (in Assura LVS) ?

Will the LVS report some error message ?

Thank you very much in advance,

DYLinux

Title: Re: Several "ground" and "Vdd" connections
Post by ACWWong on Oct 16^th, 2007, 9:39am

If both VDD pads/pins are connected together physically in metal/poly on the chip, then there is no problem. If the two VDD's will only be connected on the PCB, then in Assura LVS you can use joinableNet command. If using the Assura GUI, at the bottom click "View Additional Functions" and fill in the joinableNet Command box and add to the command list. Depending on your exact circumstances, you might need the mustJoinNet command, the details of these will be in the assura user guide in your installation path.

This post is will probably be better answered if posted in the "Physical Verification, Extraction and Analysis" part of this forum.

cheers
aw