Title :
A class-AB high-speed low-power operational amplifier in BiCMOS technology
Author :
Sen, Subhajit ; Leung, Bosco
Author_Institution :
Dept. of Electr. & Comput. Eng., Waterloo Univ., Ont., Canada
fDate :
9/1/1996 12:00:00 AM
Abstract :
A BiCMOS op-amp is described which exploits BiCMOS technology to obtain very high transconductance, slew-rate, and fast small-signal-settling response. The absence of vertical PNP transistor requires the op-amp to use a wideband, composite PMOS-vertical-NPN structure as a substitute for PNP transistors to realize a class-AB input stage of an op-amp. The AC small-signal equivalent circuit of the input stage is analyzed and methods for optimizing the nondominant pole positions to obtain fast settling are given. Measurements in the unity-gain buffer configuration indicate maximum slew-rates of 150 V/μs (rising) and 280 V/μs (falling) and a transconductance of 20 mS at a quiescent power of 20 mW from 5 V supply using a 0.8-μm BiCMOS process with peak fT of 11 GHz
Keywords :
BiCMOS analogue integrated circuits; equivalent circuits; operational amplifiers; 0.8 micron; 11 GHz; 20 mW; 5 V; AC small-signal equivalent circuit; BiCMOS technology; class-AB opamp; composite PMOS-vertical-NPN structure; high transconductance; high-speed opamp; low-power operational amplifier; slew-rate; small-signal-settling response; BiCMOS integrated circuits; Broadband amplifiers; Equivalent circuits; Operational amplifiers; Optimization methods; Signal analysis; Transconductance; Variable structure systems; Voltage; Wideband;
Journal_Title :
Solid-State Circuits, IEEE Journal of
