PNP darlington transistor ngspice .SUBCKT syntax

Schematic Simulation (Ngspice)
1

I want to simulate a PNP darlington transistor in Kicad. Here is an example of the subcircuit.

*Si 625mW 30V 1.2A pkg:TO-92B 1,2,3
.SUBCKT XMPSA65 1 2 3
* TERMINALS: C B E
Q1 1 2 4 QPWR .1
Q2 1 4 3 QPWR
.MODEL QPWR PNP (IS=1.44P NF=1 BF=107 VAF=98.6 IKF=0.96 ISE=110P NE=2
+ BR=4 NR=1 VAR=40 IKR=1.44 RE=0.333 RB=1.33 RC=0.133 CJE=258P XTB=1.5
+ VJE=0.74 MJE=0.45 CJC=37.3P VJC=1.1 MJC=0.24 TF=60.3N TR=2.61U)
.ENDS XMPSA65

I have not used subcircuits in ngspice or indeed KiCad before. Are there any simple circuits that I can try that are similar to the one referred to here in the QSPICE forum (which I started)?

I have asked about using a BC516 in the QSPICE forum, but apart from the model parameters I’m hoping it should be similar.

Also, what does the .1 refer to in the line above?

Q1 1 2 4 QPWR .1

Thanks.

2

If you have an adequate symbol with three pins, attach the subcircuit model to this symbol.

KiCad Eeschema as GUI for ngspice, tutorial for setting up the simulation offers a description how to do that. Or watch https://www.youtube.com/watch?v=V6D6I4fwQGA, at about 4min plus…

Check the model (draw a circuit diagramm by connecting the pins of the 2 transistors). The sequence in the Q line (bipolar instance) is C B E. Is it a darlington?

Q1 1 2 4 QPWR .1

Concerning the .1, have a look at the ngspice manual, chapter 7.3.1 Bipolar Junction Transistors (BJTs), which tells us about the instance of a bipolar transistor:

QXXXXXXX nc nb ne <ns> <tj> mname <area=val> <areac=val>
+ <areab=val> <m=val> <off> <ic=vbe,vce> <temp=val>
+ <dtemp=val>

There is no mention of a single number only after the model name mname. So we have to guess (or you have to look it up in the QSPICE manual). I assume that this number is equivalent to our

m = 0.1

The transistor is scaled by this value. This scaling seems to be reasonable, as the input transistor of the darlington may be smaller than its output device.

3

Thanks for your reply. Yes, it is a PNP Darlington transistor.