Hi Syafiq,

As far as I know, reversed is an indication that the transistor is connected the opposite way to the convention - in other words for an NMOS device, the source voltage is above the drain voltage. So in this netlist:

// example showing two transistors, one "reversed"
model nch bsim4 type=n

M1 (d g 0 0) nch w=1u l=0.2u
M2 (0 g d 0) nch w=1u l=0.2u

Vd (d 0) vsource dc=2
Vg (g 0) vsource dc=1

dc dc
dcOpPoint info what=oppoint where=screen

M2 shows reversed=yes, and M1 shows reversed=no.

The region information can be seen by doing "spectre -h bsim4" (or whichever device you are using). In the Operating Point Parameters section it has:

1       region=triode     Estimated operating region. Spectre outputs the number (0-4) in a rawfile. Possible values are off, triode, sat, subth,
                          and breakdown.
2       reversed          Reverse mode indicator. Possible values are no and yes.
3       ids (A)           Resistive drain-to-source current.

The numbers are in the order listed.

For a "bjt" device, it shows:

3       region=fwd        Estimated operating region. Spectre outputs number (0-4) in a rawfile. Possible values are off, fwd, rev, sat, and
                          breakdown.

so the meaning is different dependent upon the device, as I stated above.

Regards,

Andrew.

Hello Andrew,

Thanks. Your explanation has clarified my concerns.

Thanks

Syafiq

Hello Andrew,

I got one more concern. I ran dc simulation to know my circuits operating region. Basically you can load the raw file into result browser and go to dcOpInfo to check the region of transistor.  But I got quite a lot of transistor =256 transistors.  My I know how to extract the region for every single transistor?

And another question what is the difference between Id and Ids? I thought both are the same which is referring to the drain current of the MOS transistor, but sometime it gave same value, sometime NOT.

Thanks

Syafiq