I'm trying to simulate exercise 13.21(a) from Sedra-Smith, with:
- f=100 kHz
.model modn NPN(Is=6.734f Xti=3 Eg=1.11 Vaf=74.03 Bf=416.4 Ne=1.259 Ise=6.734f Ikf=66.78m Xtb=1.5 Br=.7371 Nc=2 Isc=0 Ikr=0 Rc=1 Cjc=3.638p Mjc=.3085 Vjc=.75 Fc=.5 Cje=4.493p Mje=.2593 Vje=.75 Tr=239.5n Tf=301.2p Itf=.4 Vtf=4 Xtf=2 Rb=10)
This is the circuit in pspice:
(I had to put R2=1f because otherwise the simulation didn't converge)
Since I have two conditions for oscillation:
but three electrical reactancesto size, then I have one degree of freedom so I chosed C1=L.
I also chosed I = 1*10^-6 A which should be fine because the BJT works in the forward-active region.
Unfortunaly when I simulate it I get very different results when I change the Run Time or Max Step Size values:
What's wrong? :-(
This is the project file, including the models library if someone wants to try it: