Lecture 9.1 - Load Line Analysis for Power Amplifiers

In this video, we learn about the difference between a PA and other amplifiers, primarily that we load a PA to deliver maximum power and not to deliver maximum power transfer (e.g., gain). The optimum load is one that allows the transistor to swing through its full range of current and voltage.

[abheetl]

Excellent video, very precise and concise. Thanks!

[zhesong]

Thanks Jeffrey. There is just a typo at RL > Ropt, where it should be "But not full current range".

[brothercavil]

Great video, thank you. I know it was posted a couple years ago, but if you're still checking comments, I was hoping you could clarify one thing- the load line impedance is not the same as the output impedance, is it? I ask because I'm designing a PA that outputs to a 42 ohm lossy transmission line that can be terminated with whatever I want. I can also size the transistor so the load line has the slope that I want, and if I can set it to say, 80 ohms (and terminate the transmission line with 80 ohms) but then impedance match S22 to the 42 ohms of the Tline, I could significantly reduce both drive current and DC current. Thanks!