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how to temporary short together bus in schematic for lvs

hesdeadJim

I have a pmos instance PM70<11:0> the sources are connected to vdd and the gates and drains are all connected together now the gates and sources are just floating but connected in to a single wire.   

So when I go to lvs the lvs thinks the bus is all unconnected as they are not connected to any other device. Yet in the layout I've shorted them together and as can be seen in the schematic they appear shorted together.

Is there a symbol to short together the bus? or terminate it or whatever is the correct technical term for this. As shown they (gate, drain) do not seem to short together for some reason.

  • I can't work out what you're asking. It doesn't really help with a picture of part of the schematic which doesn't show how the gate and drain are connected, nor without any indication of what's actually happening in the layout.

    You're probably going to have to supply a bit more detail if anyone is going to be able to help you here...

    Andrew

  • in reply to Andrew Beckett

    okay I suppose what I'm asking is how to combine the index nets of an instance say PM70<11:0> into one common node. So the terminals of PM70<0> would be shorted to PM70<1> and  PM70<2>... PM70<11>. The intention is that all the gates would be shorted together and all the drains  shorted together. The picture does not show this because I do not know how to do this. I was hoping there was a symbol or something to do this. At the moment Cadence schematic understands what you see though a single wire as a bus so what is needed is something else to let it know I want those nets shorted.

  • in reply to hesdeadJim

    I think I know what you're asking for. Just label the wires - if they are unlabelled, it will auto-name the nets as a bus, because there's nothing to show that they are shorted. If you label the wire as a non-bus name, then all 12 transistors will connect to the same net:

    Andrew

  • in reply to Andrew Beckett

    yes that's it! the solution is quite simple; I wish I thought of it.

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