I am trying to simulate the DC characteristic of N-channel mosfet in ADS using a tsmc018nm model. This is the imported tsmc180nm model. enter image description here

I have setup the circuit's vdd and vgs as sweep variables to plot IDS vs VDS for different gate voltages. enter image description here

The drain current is negative, what am i doing wrong? enter image description here

  • 2
    \$\begingroup\$ Tried connecting the current probe the other way around? \$\endgroup\$
    – user253751
    Mar 6, 2018 at 3:31

1 Answer 1


The current is flowing into the Drain of the transistor. The little arrow inside your probe indicates the direction of current that is counted positive. Your probe is connected in the opposite direction. Therefore the current measured is negative.

When measuring current it is important to always make sure in which direction it gets labeled positive and negative.


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