Stats

  • Locked Locked
  • Replies 5
  • Subscribers 63
  • Views 15834
  • Members are here 0
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

transistor state in Vpulse source

yefJ

Hello,  i am simulation a mixer with LO vpulse and RF with sinus source,

The mixer output spectrum works fine as shown bellow,but when i look and the BIAS state of LO transistor it shows me that  its in cutoff region as shown in the table in the end.

i understand the the LO source needs to switch the transistor from cuttoff to saturation, is there a way i can see the states in which the transistors switches?(i am not sure it goes to region 2)

Thanks 

LO source

 
RF source

OUTPUT spectrum

Parents

  • If you're looking at the operating point data, that will only show you the operating point at the DC operating point - but of course the region of the transistor will change over time if you have time-varying waveforms.

    So you might want to use Outputs->To be Saved->Select OP Parameters and ask it to save the region (or whatever) of the device you are interested in. Then you can plot this from the calculator afterwards using the OT function rather than OP function.

    Regards,

    Andrew.

  • in reply to Andrew Beckett

    Hello  Andrew, i have simulated again the qpss qpac , and  selected the region parameter .

    Afterwards i tried to  put the region variable by selecting the "ot" option, but the list is empty as shown bellow.
    Where did i go wrong ?
    Thanks

    ***************************************

    **************************************

    *************************************

  • in reply to yefJ

    OT only works with transient. You're not running transient here...

    The operating point data does not get saved during RF analyses even if you've asked to save it. It does get saved with dc sweeps and transient however.

    Regards,

    Andrew.

  • in reply to Andrew Beckett

    Hello Andrew, i managed to  make the plot by Results>plot outputs>Transient although it says enum(which i dont know what that means)

    i see that its goes into region 3(sub threshold) a lot of time instead of region 2 satuaration, so further work on the bias needs to be done on bias because sub threshold almost the same as cutoff.

    Thank you very much.

  • in reply to yefJ

    enum means it's an enumerated value rather than a measured quantity - so it's a numbered representation of the various device states. Wouldn't make sense for the axis to be in volts, or amps - so it's just indicating it's a number giving the order of the various different operating regions.

    BTW, I didn't spend any time looking at the circuit to see how it should operate so can't comment on how the circuit is actually working. I'll leave that to you!

    Andrew.

Reply
  • in reply to yefJ

    enum means it's an enumerated value rather than a measured quantity - so it's a numbered representation of the various device states. Wouldn't make sense for the axis to be in volts, or amps - so it's just indicating it's a number giving the order of the various different operating regions.

    BTW, I didn't spend any time looking at the circuit to see how it should operate so can't comment on how the circuit is actually working. I'll leave that to you!

    Andrew.

Children
No Data

Community Guidelines

The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. The community is open to everyone, and to provide the most value, we require participants to follow our Community Guidelines that facilitate a quality exchange of ideas and information. By accessing, contributing, using or downloading any materials from the site, you agree to be bound by the full Community Guidelines.