multiple digital grounds and supplies for TTL and CMOS

[stressed_user]

Hi,

In my current Multisim /ultiboard 10.0 version, there are libraries with CMOS_5V and CMOS_10V components.

When using them in a schematic, and exporting the netlists towards Ultiboard, both the VCC and VDD conections are all tied together.

In the schematic, all power connections are hidden, and automatically tied together, even when I use components from the 5V and 10V libraries.

How can I separate these supplies? Can it be done in Multisim? Can I seperate the grounds?

Can I make all these grounds or supplies visible with the master database parts?

How to place the filtering caps on the supplies? 

I hope I don't have to make new parts for each TTL and CMOS component I want to use....

Johan, stressed again...

[yyao]

Hi Johan,

You can specify hidden power supply pins. Do the following:

1. Double click on the digital component
2. Click on the Pins tab
3. Change the net of the VSS and VDD pins to your own net name (e.g. VDD10 and DGND)
4. Once you do this, you an mass edit the power pins of digital components via the spreadsheet view

To add decoupling capacitors, you can place an ordinary VDD component and edit its RefDes to be that of the net that you renamed to earlier and add capacitors as you desire. You can add ferrite beads separating the analog and digital grounds in a similar fashion. Take a look at the attached file.

Hope that helps.