An RF buffer (10) supplies a single ended output signal and differential
output signals. An average voltage of the differential output signals is
compared to a reference voltage (VR) by an amplifier (40). The amplifier
(40) provides a feedback signal for controlling the bias current conducted
by a first transistor (24) and a mirrored bias current conducted by a
second transistor (46). The bias currents conducted by the first and
second transistors (24, 46) are used to generate the differential output
signals (OUT-, OUT+) and are substantially independent of the signal level
at an input terminal (20). The signal current conducted by the first
transistor (24) controls an output transistor (66), while the signal
current conducted by the second transistor (46) controls another output
transistor (56) in the push-pull output stage of the RF buffer (10).