Bjt differential amplier design

[Andetroy]

Hello everyone. I'm building a simple bjt diff amp with active current source loading. I plan on employing negative feedback for obvious reasons related to distortion among others. I do understand that on a resistor loaded amp, the common mode gain is modelled by BRc/ri+2(B+1)Re where Re is a resistor connected between VEE and da bjt emitters. My question is, upon replacing the collector resistors with active loads, is there a way i can model the diff gain and common mode gain? I'm sorry if this sounds stupid, im a beginner.

 

[goldsmith]

Hello everyone. I'm building a simple bjt diff amp with active current source loading. I plan on employing negative feedback for obvious reasons related to distortion among others. I do understand that on a resistor loaded amp, the common mode gain is modelled by BRc/ri+2(B+1)Re where Re is a resistor connected between VEE and da bjt emitters. My question is, upon replacing the collector resistors with active loads, is there a way i can model the diff gain and common mode gain? I'm sorry if this sounds stupid, im a beginner.

Hi Andetroy

Welcome to the EDA forum .
No that is not stupid . all of us were a beginner . so it's ok .

It can be easily simulated via two different sine wave generators . which software are you using for modeling ? orcad perhaps ? ( one time in phase and the other time out of phase ) .
Best Wishes
Goldsmith

 

[Andetroy]

Hi Andetroy

Welcome to the EDA forum .
No that is not stupid . all of us were a beginner . so it's ok .

It can be easily simulated via two different sine wave generators . which software are you using for modeling ? orcad perhaps ? ( one time in phase and the other time out of phase ) .
Best Wishes
Goldsmith

thank you for replying. I'm using PSIM(as a simulator).

 

[goldsmith]

thank you for replying. I'm using PSIM(as a simulator).

Hi again
I'm not familiar with PSIM . i'm usually using Pspice . but the method is not different . use two sine wave inputs . your amp has two inputs . one of the times give both of them signals in phase and next time change phase of one of your sources .

Good Luck
Goldsmith