Schematic Entry

From NCSU EDA Wiki
Jump to: navigation, search

How do I make a schematic design?

Use ("Add->Component" menu item, or hit i) [np]mos[4] and [np]mos_elec[4] from NCSU_Analog_Parts for individual transistors (even if it's a digital design!). Logic gates are in NCSU_Digital_Parts. For power supplies, use parts from the Supply_Nets category in NCSU_Analog_Parts. Note that since the [np]mos devices don't have explicit bulk connections, the bulk node is stored in the transistor's properties (select and hit q to edit). The default node names are "vdd!" for pmos and "gnd!" for nmos, so you need to have at least have those supply nets defined.

Another important thing to note: just placing a vdd! symbol in your schematic does not define a voltage; the Supply_Nets symbols are merely node markers, used to give multiple wires a common node name. To actually define a voltage, say, for a power supply, in general you would place a vdc DC voltage source, define its voltage, connect its positive terminal to a vdd! symbol, and connect its negative terminal to a gnd! symbol. You would then attach other vdd! symbols to nodes you wish to tie to the power supply.

How do I create a layout from a schematic?

Use Virtuoso-XL ("Tools->Design Synthesis->Virtuoso-XL"). Virtuoso-XL knows about the pcells, so if you have transistors with "m" or "fingers" set, it'll do the right thing. (See cdsdoc for more info on how to use Virtuoso-XL.)

When I plot my schematics, they're so busy it's ugly. Is there a way to clean them up to get better plots?

Use the "NCSU->Create publication schematic..." menu entry. It will create a "schematic.publication" view of your schematic that is much cleaner looking than the working schematic view.

--Slipa 11:46, 27 February 2006 (EST)