Naming conventions in schematic and layout

[BB11]

Hello

I have a question regarding naming conventions in layout and schemtics. Suppose I use vdd! and vss! to represent in my layout for vdd and gnd. When i run a testbench simulation, i assign the local value vdd! to the master value vdd. But i still see that my ouput is not as expected. Could anyone help me with this?

Thanks

BB

 

[BradtheRad]

It was too simple just to use two labels. Someone had to invent other schemes just to confuse things.

There are several labeling schemes:
Vcc / Vee
Vdd / Vss
V+ / gnd
etc....

Furthermore if you have a bipolar supply, what do you call the negative polarity? We tend to understand Vdd and Vss (or Vcc and Vee) are already taken to mean V+ and ground. So it looks like it's all relative.

I guess it's too hard to settle on a comprehensive standard at this point.

As for how to make progress with your simulation, try a different set of labels. Or eliminate a few labels and substitute a voltage source with a numeric value.

Avoid connecting two voltage sources directly together.

Also, I have wondered if there might be a situation in a simulator, where it will permit us to label two points 'ground', yet it turns out to be impossible for the simulator to maintain both of them at 0V. This would be an error that would put the strain on our ability to track it down.