Sunday, February 17, 2019

100 MHz amp - comparing sim to calculated

This is the circuit
I bias
V emitter
Q1 collector current
Input and output
Time base adjusted to show waveform

The math and the model follow each other fairly well. The math was using ß = 93. I think my model uses ß = 125. I expected a little variation because of this.

I assumed a 1k load and used the 4T:14T FT37-61 transformer. The transformer could be adjusted for the desired Zout.


  1. oh wow that is so much better than I expected!!!!

  2. I looked at the spice model and found ß = 125. I think you used 97. You are probably closer to the actual. I looked at the datasheet and 125 was on the high end of the range.