MAESTRO: Print -> DC operating point gives out different operating points for different MOSFETs in the design

Dear akaraguppi,

akaraguppi said:

I see all parameters for a few MOSFETs but I see only 7 parameters for others. In the attached image you can see that for MOSFET M50 , I can see only 7 parameters however for M38 I can see all of them.

I apologize, but I am confused by your question and am not sure how to provide a concrete answer. I only see 6 parameters for M50 in the screenshot you included and it is not clear to me that "all" the parameters are provided for M38. I am also not sure I understand all the "sweeps' you have listed. Further, I am not sure the methodology you are using to saving the operating point information.

What I might suggest is you review the contents of a recent reply to a Forum post regarding displaying specific operating point parameters for devices. There are some links to documents and a video that detail the methodology to save and display particular operating point parameters in which you are interested. I hope this will help you a bit. Perhaps reviewing this post might allow you to clarify the issue you are wrestling to understand and reply with added information.

The recent Forum post regarding viewing specific operating point parameters is at URL:

https://community.cadence.com/cadence_technology_forums/f/custom-ic-design/52194/results-display-window/1384734#1384734

Shawn

I have run a dc simulation using MAESTRO and I understand that all parameters for M38 are not visible in the image I uploaded but if I scroll to the right I see them all. They appear horizontally hence I couldn't capture them all in the picture. But for M50 I see only 7 parameters as can be seen in the picture.

I am attaching 7 images in which I can see all parameters for M38 after the dc simulation, however, I see only 7 parameters for M50. My question is why can I see all parameters for one MOSFET and not for all?

First thing to check is whether M50 and M38 are the same type of transistor. It's possible that one of them is modelled as a subckt model, and the CDF may have only been set up to expose a limited set of operating point parameters - whereas if the other device is directly modelled it may expose all of the operating point parameters. So what devices are M50 and M38, and which PDK are you using?

Also, how are you printing the operating point parameters? I'd expect the operating point parameters to be printed this way if you're doing a sweep in ADE (rather than a DC sweep in the simulator - which wouldn't affect the operating point results anyway).

Not sure it is ultra-critical in this case, but whilst I'm asking questions, which IC-subversion are you using (Help->About in any window will tell you this)?

Andrew

Hi Andrew, 

As you mentioned rightly, the MOSFET was modelled as a sub-circuit and going into it helped me get all parameters. Thanks! 

Hi Andrew, 

As you mentioned rightly, the MOSFET was modelled as a sub-circuit and going into it helped me get all parameters. Thanks!