Building a PNP Cascode: A Design Exploration

[STEMucator]

Hi everyone. I have seen the design for an NPN Cascode many times, but I want to build a PNP Cascode. I have scoured the internet for a standard design, but to no avail.

The image below is that of a NPN Cascode. I want to create a PNP cascode by flipping things around. I have placed a red line through the circuitry. On the left side of the red line I expect nothing to change when building the PNP Cascode. On the right side of the red line is where I expect things to change.

Here is what I am thinking:

1. I will turn transistors $Q_1$ and $Q_2$ into PNP transistors.

2. In the emitter of $Q_2$ there will be no resistor, only the power supply connection $V_{CC}$.

3. Between the collector of $Q_2$ and the emitter of $Q_1$, I will place $R_C$ just before the loading circuit. Then I will place the loading circuit.

4. Just after the loading circuit, I will place $R_{E1}$, $R_{E2}$ and $C_E$.

5. The collector of $Q_1$ will then be wired to ground.

Does this sound reasonable?

If not, does anyone know what the standard design would look like and could show me?

Thank you.

 

[STEMucator]

I took the time to make a quick blackboard sketch of what I thought it looks like:

Seem reasonable?

 

[Jony130]

Your PNP version is wrong, and will not work. The Cascode is CE stage + CB stage.
The correct circuit look like this

 

[STEMucator]

Your PNP version is wrong, and will not work. The Cascode is CE stage + CB stage.
The correct circuit look like this

It was just hitting me and I came back and saw your post.

I drew this:

https://gyazo.com/d3cfd6526d94f4ce09a6ab1885debf01

It looks pretty much like yours, except the capacitor $C_E$ should be grounded.

 

[Jony130]

I drew this:
https://gyazo.com/d3cfd6526d94f4ce09a6ab1885debf01

Almost right. R3 resistor must be connected to VCC and R1 to GND.
To convert any NPN circuit into PNP version simply amply this rules:
1 - Change transistor type NPN into PNP
2 - NPN ground now becomes PNP VCC
3 - NPN VCC change to PNP GND (simply reverse the power supply polarity).
4 - If necessary reverse electrolytic capacitor polarity

It looks pretty much like yours, except the capacitor $C_E$ should be grounded.

But this change is not necessary (Vcc is also a good place).