Hi,
I am running a dc simulation using Spectre, the simulation is very simple, I am just using and Ideal dc supply from the analogLib to pump a certain DC current in the drain of a transistor and I repeat the test for different transistors (mainly different sizing).
What I don't understand is why when I am trying to report the dcOpInfo parameters (either Id or Ids) I always see a small error delta for some specific instances, although they all have the same current going through them from an ideal supply ?
Tolerance options are set to default : reltol: 1e-3 Vabstol:1e-6 iabstol:1e-12
Example below for Ids = 5uA and 10uA
M12_135n/M0
id = 5u ids = 5u
/M3_36n/M0
id = 5.005u ids = 5.005u
/M4_135n/M0
id = 5.002u ids = 5.002u
/M4_36n/M0
id = 5.006u ids = 5.006u
/M4_72n/M0
id = 5.007u ids = 5.007u
/M4_8n/M0
id = 5u ids = 5u
/M12_135n/M0
id = 10u ids = 10u
/M8_72n/M0
id = 10.01u ids = 10.01u
/M8_8n/M0
id = 10u ids = 10u
Best Regards