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Hi,

I'm trying to model a circuit that requires a MJ4502 transistor, I've looked at the parameters that I can set on the PNP transistor component but I can't find any information on half of the parameters in any MJ4502 datasheet. Does anyone know what the parameters should be?

Thanks,

Joe

About datasheet, device and simulation model parameters

To edit models see:

https://www.circuitlab.com/docs/faq/#q_add_custom_models

https://www.circuitlab.com/forums/modeling-and-simulation/topic/sq59q7zy/model-a-low-leakage-schottky-diode/

You cannot simply map datasheet parameters onto a device simulation model.

However, if you can find a spice model for your target device, then you can edit the relevant parameters of one of the built-in CL models and use that in your circuit.

Here's a spice model for the MJ4502:

http://www.onsemi.com/pub_link/Collateral/MJ4502.SP3

For more information please see this thread:

https://www.circuitlab.com/forums/basic-electronics/topic/9dg62j8d/help-for-beginners-hobbyists/

Note that there are some unanswered questions about editing CL model parameters (which may not affect you anyway):

https://www.circuitlab.com/forums/feature-requests/topic/6k7v65fx/questions-about-editing-model-parameters/

SPICE parameters for devices have little to do with datasheet specifications. They are much more to do with semiconductor physics and the particular process under which a given device is manufactured at the foundry. Consequently it is not always a simple task to map datasheet information onto the model parameters.

If you want to try to understand more about what the SPICE - and hence CL - parameters mean in diodes, bipolar transistors and MOSFETs, then you might like to have a look at:

http://www3.imperial.ac.uk/pls/portallive/docs/1/56133736.PDF

with individual slide sets:

http://www3.imperial.ac.uk/pls/portallive/docs/1/7292571.PDF

http://www3.imperial.ac.uk/pls/portallive/docs/1/7292572.PDF

http://www3.imperial.ac.uk/pls/portallive/docs/1/7292573.PDF

For more detailed information about bjt's in particular, have a look at this book:

http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=01480193

available from:

http://www.lulu.com/spotlight/iangetreu

and

http://www.amazon.com/Modeling-Bipolar-Transistor-Ian-Getreu/dp/B000EYPQLU

Another excellent (and free) book about transistor modelling, go to:

http://www.aeng.com/spice_modeling.htm

and register to get a copy of:

Definitive Handbook of Transistor Modeling

Thanks, I think I'm getting somewhere now