BJT Spice model

Thread Starter

edba

Joined Dec 18, 2017
5
Hi

I am trying to find a good but simple tutorial about how to alter the parameters of the NPN/PNP Gummel and Poon model in LTSpice to be able to create any transistor you wish. At the moment I am just trying to model an old late 60s transistorised record player amplifier. The two transistors used for the preamplifier are silicon BC109 and BC107. The two output transistors are germanium AC131 and AC186. I noticed on this site they have a very helpful spice model section for diodes (https://www.allaboutcircuits.com/textbook/semiconductors/chpt-3/spice-models/) but no such section for BJT transistors? I have looked around on the internet and have found some university papers, but they tend to be very complicated and academic. I am looking for a practical guide to just altering the parameters so you get the basic properties of the transistor you trying to simulate i.e. base to emitter diode drop, forward gain, transistion frquency etc.

Can anyone help?

Br

Edba
 

crutschow

Joined Mar 14, 2008
26,775
but the datasheet usually has all the desired parameters?
No.
The data sheet parameters are relatively simple, and not readily converted to the Gummel and Poon model parameters used in SPICE.

The easiest is to look at the data sheet and find a similar transistor in the SPICE model listing.
That likely will be good enough for most simulation purposes.
 

Bordodynov

Joined May 20, 2015
2,803
Here is a selection of circuits in which I investigated bipolar transistors. Some circuits I used to extract spice parameters and fit to datasheets. Unfortunately in some circuits the comments are in Russian. You can ask questions about these circuits.
 

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Papabravo

Joined Feb 24, 2006
15,518
Here is a selection of circuits in which I investigated bipolar transistors. Some circuits I used to extract spice parameters and fit to datasheets. Unfortunately in some circuits the comments are in Russian. You can ask questions about these circuits.
Thanks - very useful circuit and simulation concepts.
 
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