Title :
A low-voltage CMOS rail-to-rail class-AB input/output opamp with slew-rate and settling enhancement
Author :
Lin, Chi-Hung ; Ismail, Mohammed
Author_Institution :
Dept. of Electr. Eng., Ohio State Univ., Columbus, OH, USA
Abstract :
A low-voltage CMOS rail-to-rail op amp with high slew-rate and fast-settling is presented. The input stage is composed of the complementary differential pairs, a pair of modified current-mode maximum selecting circuits (Maximum Current Selecting Circuit II) and a class-AB feedback loop circuit. It achieves rail-to-rail operation, constant-gm, high slew-rate and fast-settling. With this opamp topology, the design can be easily performed for a wide-range of capacitive loads with a large bandwidth-to-power-consumption ratio. With 2 μm and 0.5 μm technology respectively, the op amp has a high DC gain (⩾84 dB), and has a bandwidth-to-power-consumption ratio of 13.6 MHz/mW and 25.8 MHz/mW with capacitive loads of 20 pF, 86 V/μs, S0 V/μs slew-rate and 159 ns, 36 ns settling-time
Keywords :
CMOS analogue integrated circuits; feedback amplifiers; operational amplifiers; 0.5 micron; 159 ns; 2 micron; 36 ns; DC gain; bandwidth-to-power-consumption ratio; capacitive loads; class-AB feedback loop circuit; complementary differential pairs; current-mode maximum selecting circuits; low-voltage CMOS; opamps; rail-to-rail class-AB I/O amplifier; settling enhancement; slew-rate enhancement; Circuit topology; Feedback circuits; Feedback loop; Mirrors; Power dissipation; Rail to rail inputs; Rail to rail operation; Rail to rail outputs; Switched capacitor circuits; Very large scale integration;
Conference_Titel :
Circuits and Systems, 1998. ISCAS '98. Proceedings of the 1998 IEEE International Symposium on
Conference_Location :
Monterey, CA
Print_ISBN :
0-7803-4455-3
DOI :
10.1109/ISCAS.1998.704473
