
272 HYBRID AND MONOLITHIC MICROWAVE INTEGRATED CIRCUIT AMPLIFIERS
ries and shunt feedback resistors (Re and Rf) as the previous circuit. All resistors ex-
cept Rbi,~ are internal to the MIC device.
A Darlington amplifier, also called a
Darlington pair
or
superbeta transistor,
consists of a pair of bipolar transistors (Q1 and Q2) connected such that Q1 is an
emitter follower driving the base of Q2, and with both collectors connected in par-
allel with each other. The Darlington connection permits both transistors to be
treated as if they were a single transistor with higher than normal input impedance
and a
beta
gain ...