Stats

  • Locked Locked
  • Replies 3
  • Subscribers 126
  • Views 1811
  • 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

Storing config of a cell in a file/cellview

itos

Hi,

Is it somehow possible to store design variables of a cell in a config-like cellview or file?

Here is what I mean: Suppose I design a simple opamp for I which create a triangle symbol view and use it in many other places. Now when I design the amplifier I have all the widths, lengths, bias currents in my ADE L view as Design Variables. I can sweep them until they match and then I fix them. Now, 2 weeks later I need to change the amplifier. I need to replace all the static values by design variables, design the amplifier and re-replace the values again with their static values.

This is extremely error prone (and I always make mistakes), particularly since so many values are interrelates (e.g. the widths in a differential configuration are the same and the biasing branches are just some multiple).

What I envison is some sort of pPar which takes the actual values from a config file or config cell view. Then it's also way easier to keep an overview on the design and archive specs.

What I do not want: Store the values in an scs file and use "Simulation files". It just does not work because ADE L always imports the design variables into the window and then simulation fails if if they are not set (and if they are set, they overwrite the values from the scs file). Supposedly copyDesignVarsFromCellview should fix this (see 

ADE L Design variables from include files
Hi, I define lots of design variables. When I use "Copy from Cellview" in ADE L, all the undefined design variables are detected and I can fill them. I used this extensively. Now I would like to generate…
By in Cadence Technology Forums > Custom IC Design
2 replies
Latest by
) but this is just ignored. (Even if, I would not consider it a clean solution

copyDesignVarsFromCellview
copyDesignVarsFromCellview
copyDesignVarsFromCellview)

  • Quek

    Hi itos

    When tuning device parameters, it is actually no longer necessary to go through the traditional method of replacing the property fields with ADE variables. In both Explorer, Assembler and also ADE-XL, we can use the "Variables and Parameters" assistant as follows:

    a. Select the target device in schematic
    b. Parametrized the required device parameter as follows in the "Variables and Parameters" assistant
    c. Replacing the value in the assistant does not affect the schematic. The new value will be automatically used in Spectre netlist
    d. Perform simulation and tune parameter until the specs have been meet

    In this snapshot, I have parametrize "w" for device M1. We can see that the design (schematic) value is 10u but I have changed it to 11u in the assistant. 11u and not the original 10u will be used in the netlist.




    If  you have access to ADE-XL, I think this might be what you need.


    Best regards
    Quek

  • Andrew Beckett

    The other thing you can also do with the Variables and Parameters assistant is save sets of variable/parameter values (or sweeps) to a "setup state". That's the box and icons at the top of the image that Quek shared. Then it's easy to switch back and forth between fixed global variables and sweeps, or to enable certain combinations.

    Also the parameters can easily be set up to be matched parameters between a group of devices (without having to put variables on everything), or you can setup "ratio" parameters (such as when you've got a value with is N times another and you want to maintain that ratio whilst sweeping the unit value).

    If it was just a matter of recording a set of variables, then of course you could do that with ADE L - you just need to save the state and just save the variables. However, the problem with that is that  you need to modify the schematic to reference all these global variables, which is awkward and hard to maintain. As Quek said, the parameterisation capability in ADE XL (and ADE Explorer and Assembler in IC617) means you don't have to edit the schematic at all; you can override values without actually modifying the schematic at all. Once you're happy with a result, you can backannotate the values onto the actual schematic (i.e. update the schematic to reflect the values you're happy with).

    Regards,

    Andrew 

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.