Is there a generic transistor model for Capture CIS?

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Discussion Overview

The discussion revolves around the search for a generic transistor model suitable for use in Capture CIS, particularly focusing on the ability to easily edit parameters such as K, V-Threshold, and B_f without altering channel lengths and widths. The conversation touches on the use of schematic capture tools and circuit simulation.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant seeks a generic model for MOSFET/BJT transistors in Capture CIS that allows easy parameter adjustments.
  • Another participant clarifies that MOSFET behaviors are influenced by width (W) and length (L), while BJT behaviors depend on fundamental parameters like those from the Ebers-Moll or Gummel-Poon models.
  • A participant suggests that default SPICE models may suffice for general use, referencing older discrete parts as a benchmark for performance.
  • One participant acknowledges the dependency of transistor behaviors on W and L but mentions that educational contexts often simplify this to parameters like K, threshold voltage, and early voltage for intuitive analysis.
  • A later reply offers a specific model from the BREAKOUT library, indicating that it allows for the editing of the parameters the original poster is interested in.

Areas of Agreement / Disagreement

Participants express varying levels of agreement on the importance of W and L in determining transistor behaviors. There is no consensus on a single generic model for Capture CIS, and the discussion includes multiple perspectives on the adequacy of existing models.

Contextual Notes

The discussion highlights limitations in the availability of generic models and the potential need for customization in simulation tools. There is also an acknowledgment of the differences in transistor characterization in educational settings versus practical applications.

Who May Find This Useful

This discussion may be useful for individuals interested in circuit simulation, schematic capture, and those seeking to understand the modeling of transistors in educational or practical contexts.

KingNothing
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I have been searching for a generic model of MOSFET/BJT transistors for Capture CIS. I would like something where I can easily edit K, V-Threshold, and B_f (beta-f) without messing with channel lengths and widths and such.

Does anyone know where I can download such a thing?
 
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Capture CIS is a schematic capture tool. Are you saying you are hooking it up to a circuit simulator?

MOSFET behaviors are strongly dependent on W and L. BJT behaviors depend on a handful of basic parameters starting at Ebers-Moll or Gummel-Poon as minimums.

The defaults used by various SPICEs are probably good enough if you don't care much about specific implementation. They give "reasonable" behaviors for circa 1970 era available discrete parts (e.g. 2N3406/2N2222 BJT levels of performance for the default BJT parameters).

I don't know the ins-and-outs to stuffing Capture CIS with model parameters or of hooking it up to a circuit simulator.
 
I understand that the behaviors are dependent on W and L. In colleges however, transistors are generally characterized by K (conductance parameter), a threshold voltage, and an early voltage (Va) which all depend on W and L and a few properties of the materials. This is to make the analysis generally more intuitive.

I did err about Capture CIS. I use it somewhat interchangeably with PSPICE for schematic capture and simulation. How can I go about making my own PSPICE models then?
 
Do you have the BREAKOUT library? The models in there are very generic and the parameters you mentioned can be edited. For example, this a model I used for an assignment not too long ago-

.model Mbreakn NMOS VTO=1 KP=4E-3 W=1 L=1 LAMBDA = .1

I'm pretty sure that's what you're looking for.
 

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