Role of the choke


Joined Jun 2, 2021
An RF choke “chokes out” or (ideally) doesn’t allow RF signals to flow through it. It serves as a high impedance (ideally an open) component for RF signals looking into that signal path. You can think of an RF choke as a high-valued, ideal inductor. Ideal inductors have a high impedance at high frequencies and a low impedance at low frequencies (ZL = jwL). Hence, they’ll attenuate high-frequency signals and feed low-frequency signals (or DC).

In this application, the RF choke will allow DC to flow down to OUT PIN1, biasing the node, but block the RF output signal from leaking into the DC biasing network. We don’t want RF to leak into the DC biasing network so that we can maximize the RF power delivery to the load.

Hope this helps