Updated based on feedback with better screenshots (I hope) - I am also working on getting the files onto a file sharing site so they can be accessed at full resolution
I am really confused about the attached LTSpice circuit behavior
The voltage source V2 is simply a 5V supply and Voltage source V1 is a square wave of 40us period (5 volts)
I run the simulation - with the 5V square wave I would expect the Q1_Collector voltage to drop to 0 within 500ns of Q2 collector voltage going to 5 volts however the Q2_Collector voltage does not drop to 0 for 3us and I am trying to understand why.
On the plot show below - I am plotting collector voltages at net Q2_Collector - in Green and voltages at Q1_Collector in purple - The cursors show how when the Q2_Collector voltage rises to 5Volts the Q1_Collector voltage does not switch off for almost 3us
I see from the data sheet that Q1 has a switch off time of 70ns and a storag time of 70~100ns. I created the circuit to model the switch off times and I noticed that the turn off times I observe in the simulation are of the order of microseconds (2-3) microseconds to be precise.
I also built a circuit to see if what I was observing was a simulation issue but the circuit showed a similar behavior - infact I saw switch off times of almost 6us.
My question - can someone please help me understand why I am seeing such a difference between what I would expect from the Datasheet? Obviously I am doing something wrong and just cannot get what.
I am working on posting links to the files if these are still not very clear.