- Can you briefly describe two ways in which the gain of the source follower can be improved (closer to one)?
Looking at the gain equation for the source follower circuit:
We can observe that there are to parameters which the gain is dependent on. Therefore, the two alternatives to get a closer to ideal gain (A = 1) are:
- Decrease the rS value, by increasing ID (not preferable due to the dependance between ID and RL).
- Increase the value of RL – source load resistor (this can be achieved by adding a current mirror circuit instead of the source load resistance, which provides a constant current ID and a high output resistance, increasing the value of RL)