Optimal design of low power nested GM-C compensation amplifiers using a current-based MOS transistor model

A sound design of low power multistage amplifiers is presented. The amplifiers are stabilized by Nested Transconductance-Capacitance Compensation (NGCC). The key for an optimal design is a current-based MOSFET transistor model, which allows the amplifiers to be designed in moderate inversion. With 2 V supply voltage and 10 k/spl Omega//20 pF load, a four-stage amplifier implemented in a 1.2 /spl mu/m n-well CMOS process achieved 1.03 MHz gain bandwidth product, 103 dB open loop gain and 62.7/spl deg/ phase margin with a power consumption of 0.3 mW. The active area of the amplifier is 0.0052 mm/sup 2/. With the same specifications, a three-stage amplifier was also integrated in the 1.2 /spl mu/m n-well CMOS process. Compared to the design in strong inversion, both amplifiers satisfy the specifications while the power consumption is reduced by a factor of 3.

[1]  Willy Sansen,et al.  A CMOS large-swing low-distortion three-stage class AB power amplifier , 1990 .

[2]  C. Galup-Montoro,et al.  A current-based model for the MOS transistor , 1997, Proceedings of 1997 IEEE International Symposium on Circuits and Systems. Circuits and Systems in the Information Age ISCAS '97.

[3]  E. Sanchez-Sinencio,et al.  A multistage amplifier topology with nested Gm-C compensation for low-voltage application , 1997, 1997 IEEE International Solids-State Circuits Conference. Digest of Technical Papers.

[4]  John M. Acken,et al.  Special applications of the voting model for bridging faults , 1993 .

[5]  R. Hogervorst,et al.  A programmable 1.5 V CMOS class-AB operational amplifier with hybrid nested Miller compensation for 120 dB gain and 6 MHz UGF , 1994, Proceedings of IEEE International Solid-State Circuits Conference - ISSCC '94.

[6]  Denis Flandre,et al.  A gm/ID based methodology for the design of CMOS analog circuits and its application to the synthesis of a silicon-on-insulator micropower OTA , 1996, IEEE J. Solid State Circuits.

[7]  R. Castello,et al.  A CMOS Low Distortion Fully Differential Power Amplifier With Double Nested Miller Compensation , 1992, ESSCIRC '92: Eighteenth European Solid-State Circuits conference.

[8]  Kenneth R. Laker,et al.  Design of analog integrated circuits and systems , 1994 .

[9]  Johan H. Huijsing,et al.  Frequency Compensation Techniques for Low-Power Operational Amplifiers , 1995 .