A multi-stage output buffer is disclosed. The output buffer includes an
emitter follower circuit coupled to a differential input that is
configured to provide a substantially high input impedance at an input
thereof, and provide a substantially low output impedance at an output
thereof. An emitter coupled pair circuit is coupled to the output of the
emitter follower circuit, and is configured to amplify the signal and
further isolate an input circuit. The buffer further includes a
base-grounded configuration transistor circuit coupled to an output of
the emitter coupled pair circuit and having an output coupled to the
differential output of the multi-stage output buffer. The base-grounded
transistor circuit reduces a load impedance at the output of the emitter
coupled pair circuit, improves decoupling of the external load from an
input circuit when coupled thereto, and increases the output power.