The squarewave has offset voltage because it comes from the emitter of the output darlington that has no negative feedback. The darlington has two base-emitter voltage drops.
I see, thanks
What was the problem you had in LT Spice?
Thanks
Adam
I was getting the same flat output, as I attached in my first post.
Managed to crack the issue
So first thing I did was just go 100% as per data sheet, so all values are the same as above, except the supply voltage was changed from +/-9 to +/-15..
I took out the initial conditions and simulated.... nothing
Then I put an initial condition on the pulse o/p, and it came to life !!
As per values of the datasheet, it was oscillating at about 37 MHz so any sort of Vc above 1 volt resulted in saturation again....
I changed Rc and C and have it oscillating in the KHz range...
It also allows the supply votage to be dropped again to +/-9V