Y-parameters and parameter extraction formulas for the common source, common source w/ source degeneration and common gate arrangements based on the transistor equivalent circuit.

1. RF amplifier design
Useful expressions
Ilias Sourikopoulos Dec2018

2. 1) Y,S,T parameter relations
2) Y-parameters of the equivalent circuit for single transistor
topologies.
-common source
-common source w/ source degeneration
-common gate
3) Extract equivalent circuit components from a foundry model
4) Establish amplifier design flow with T and S-params
This presentation
Ilias Sourikopoulos Dec2018

3. Y to S-parameter
two port
network
port 1 port 2
Ilias Sourikopoulos Dec2018

4. Cascading stages with T-params
two port
network
port 1 port 2
Ilias Sourikopoulos Dec2018

5. Cascading stages with T-params
So design flow could encompass:
- Finding Y-parameter matrix for each block. (=electrical analyses)
- Y-to-T transform for system composition.
- T-to-S transform for visualization of standard metrics.
Next up: Present Y-parameter matrices for common transistor arrangements
Ilias Sourikopoulos Dec2018

6. The transistor equivalent circuit
the standard textbook MOSFET equivalent circuit for
frequency response calculations

7. Common source stage Y-parameters
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8. Common source+deg stage
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9. Common source+deg stage Y-parameters 1/2
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10. Common source+deg stage Y-params 2/2

11. Common gate Y-parameters

12. Quick parameter extraction
From transistor Y-params
to equivalent circuit components
Ilias Sourikopoulos Dec2018

13. Accuracy is pretty ok
Comparing analytical expressions i.e equivalent circuit, against transistor
foundy model sims. Circuit extraction based on single frequency
Ilias Sourikopoulos Dec2018

14. Conclusions
Analytical expressions enable quick and
accurate amplifier design flow
As always more time on paper (or excel or
math tool) less time on simulator
Simulate to verify not to discover
Ilias Sourikopoulos Dec2018