Title :
Class AB CMOS amplifiers with high efficiency
Author :
Callewaert, Ludwig G A ; Sansen, Wily M C
Author_Institution :
Dept. Elektrotech., Katholieke Univ. Leuven, Heverlee, Belgium
fDate :
6/1/1990 12:00:00 AM
Abstract :
A new class AB CMOS operational-amplifier principle is presented. A transconductance amplifier based on this principle exhibits small-signal characteristics comparable to those of a conventional OTA. It has, however, a superior current efficiency and its settling time is not slew-rate limited. The new class AB principle can also be used in an output stage with a well-defined quiescent current, a rail-to-rail output swing, and a good driving capability. A two-stage amplifier with both the input and output stages based on the new principle has been realized. It features a rail-to-rail input and output common-mode range, a gain-bandwidth of 370-kHz, a settling time of less than 5 μs independent of the applied step, and a power consumption of 247 μW. It drives a resistive load of 3 kΩ in parallel with a capacitive load of 400 pF when operated on a 2.5-V/-2.5-V power supply
Keywords :
CMOS integrated circuits; linear integrated circuits; operational amplifiers; 2.5 V; 247 muW; capacitive load; class AB CMOS operational-amplifier principle; current efficiency; driving capability; efficiency; gain-bandwidth; output common-mode range; power consumption; quiescent current; rail-to-rail output swing; resistive load; settling time; small-signal characteristics; transconductance amplifier; two-stage amplifier; Circuits; Energy consumption; MOS devices; Operational amplifiers; Power amplifiers; Power supplies; Rail to rail inputs; Rail to rail outputs; Transconductance; Voltage;
Journal_Title :
Solid-State Circuits, IEEE Journal of
