A low-voltage CMOS rail-to-rail class-AB input/output opamp with slew-rate and settling enhancement

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-g/sub m/, 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 /spl mu/m and 0.5 /spl mu/m technology respectively, the op amp has a high DC gain (/spl ges/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//spl mu/s, S0 V//spl mu/s slew-rate and 159 ns, 36 ns settling-time.

[1]  G. Ferri,et al.  A 1.3 V op/amp in standard 0.7 /spl mu/m CMOS with constant g/sub m/ and rail-to-rail input and output stages , 1996, 1996 IEEE International Solid-State Circuits Conference. Digest of TEchnical Papers, ISSCC.

[2]  Subhajit Sen,et al.  A class-AB high-speed low-power operational amplifier in BiCMOS technology , 1996 .

[3]  R. Hogervorst,et al.  A compact power-efficient 3 V CMOS rail-to-rail input/output operational amplifier for VLSI cell libraries , 1994, Proceedings of IEEE International Solid-State Circuits Conference - ISSCC '94.

[4]  E. Seevinck,et al.  A versatile CMOS linear transconductor/square-law function , 1987 .

[5]  Willy Sansen,et al.  A fully differential 1.5 V low-power CMOS operational amplifier with a rail-to-rail current-regulated constant-g/sub m/ input stage , 1997, Proceedings of CICC 97 - Custom Integrated Circuits Conference.

[6]  S.H.K. Embabi,et al.  The limitation of CMRR in low voltage operational amplifier with N-P input pairs , 1996, 1996 IEEE International Symposium on Circuits and Systems. Circuits and Systems Connecting the World. ISCAS 96.

[7]  R. F. Wassenaar,et al.  CMOS low-voltage operational amplifiers with constant-gm rail-to-rail input stage , 1992 .

[8]  G. Klisnick,et al.  An efficient and high-performances CMOS op amp with rail-to-rail mode and high CMRR , 1996, 1996 IEEE-CAS Region 8 Workshop on Analog and Mixed IC Design. Proceedings.

[9]  Mohammed Ismail,et al.  High slew rate micro-power CMOS OTA with class AB input stage , 1997, Proceedings of 40th Midwest Symposium on Circuits and Systems. Dedicated to the Memory of Professor Mac Van Valkenburg.

[10]  Michael M. Green,et al.  Simple rail-to-rail constant-transconductance input stage operating in strong inversion , 1996, Proceedings of the 39th Midwest Symposium on Circuits and Systems.

[11]  J. P. Tero,et al.  Compact CMOS constant-g/sub m/ rail-to-rail input stage with g/sub m/-control by an electronic zener diode , 1996 .

[12]  M. E. Pulkin,et al.  A new CMOS differential amplifier circuit for improved slew rate performance , 1996, Proceedings of the 39th Midwest Symposium on Circuits and Systems.

[13]  J.H. Huijsing,et al.  Compact 1.8 V low-power CMOS operational amplifier cells for VLSI , 1997, 1997 IEEE International Solids-State Circuits Conference. Digest of Technical Papers.

[14]  B. Hosticka,et al.  A very-high-slew-rate CMOS operational amplifier , 1989 .

[15]  Mohammed Ismail,et al.  A low-voltage low-power CMOS opamp with rail-to-rail input/output , 1997, Proceedings of 40th Midwest Symposium on Circuits and Systems. Dedicated to the Memory of Professor Mac Van Valkenburg.

[16]  C. Gontrand,et al.  A fast-settling 3 V CMOS buffer amplifier , 1996 .

[17]  Johan H. Huijsing,et al.  Compact CMOS constant-gm rail-to-rail input stages with gm-control by an electronic zener diode , 1995, ESSCIRC '95: Twenty-first European Solid-State Circuits Conference.

[18]  R. F. Wassenaar,et al.  Rail-to-rail constant-gm input stage and class AB output stage for low-voltage CMOS op amps , 1994 .