Hi Henrik -- > > For the current project i'm drawing I need a few new symbols (PGA2310 from > TI and few devices from Allegro). How do I draw a symbol that needs three > different power connections and three different ground connections using > net-attributes? Now I have drawn pins for the power and ground stuff.
This is my opinion only. If your parts are analog parts, or have analog and digital sections (e.g. an A/D), my opinion is that the pwr/gnd connections should be brought out on pins explicitly. For power nets this is good practice because then you can explicitly attach the power decoupling/bypass networks to the pin. For GND, this is good practice because you often want to attach analog GND pins to an analog GND plane, whereas digital GND pins often go to a separate digital GND plane. If your parts are digital parts, but require independent decoupling networks (like some communications chips, or some high-speed digital parts), the same considerations apply. THerefore, bringing the pwr/GND connections out to pins is a good idea. If you have a low-speed, generic digital part with, say, three pins which all attach to the same pwr/GND net, then you can probably just attach the pwr/GND nets to the same net using an attribute. I don't know how to do this, however, since I generally always attach pwr/GND nets to pins due to the nature of my projects . . . . Stuart
