BJT Cascode Amplifier

[LED]

Hi, I have started working with a cascode amplifier, based on two identical BJT transistors.

Here is my assignment:


I have found this assignment very difficult, as there are a lot of unknown variables that make it seem unsolvable. Here are the equations I could come up with:


Unfortunately, none of those equations helped me to get to the answer, as they all end up in dead-ends of unknown values. How do I find the values of Rc and RL? Or R1,2,3?

What am I doing wrong, or what am I missing? What should be my next step in designing the amplifier?
I feel completely stuck.

 

[crutschow]

Start with the desired collector current and work from the bottom up.
Think about how the circuit works.
Hint: The collector current of Q1 is determined by Q1's emitter voltage across Re, and Q1's emitter voltage is determined by Q1's base voltage.
Do you know what the typical Vbe of a BJT is when operating?

 

[danadak]

A partial solution flow -

https://www.bg-elektronik.dk/generally/transistor/Cascode%20Amplifier%20Design.pdf

Regards, Dana.

 

[Keonte45]

Hi LED,

Have you resolved your assignment?