Effect of Parallel Devices in ERC Report


I'm checking over-voltage, I have a netlist with two parallel transistors of the same type, both transistors violation Vgs rule, but the tool only reports one transistor. Is it because the two transistors got merged inside the tool?


Yes if the transistors are same model name, same properties, and ALL same connections, then they become:

One instance that is reported for any violations, counted in subgraph recognition, and/or invoked by a user script. Basically, this is a "master" or "head" instance that defines circuit behavior.

Another instance that is only invoked when asking for device counts, doing cross-probe, determining additional driver strength or load. This one is probably shown as "..._Multi1". You can think of this one as a "slave" to the other.