CMOS Low-Power Variable-Gain CMFB-Free Current Feedback Amplifier for Ultrasound Diagnostic Applications

A CMOS current feedback amplifier (CFA) for ultrasound diagnostic applications is proposed. Unlike traditional CFAs, this design employs a new symmetrical and compact architecture, without the use of common-mode feedback (CMFB) circuitry. The design proposes an active feedback technique to drastically enhance the gain-bandwidth independence. It is also the first CFA to adopt Miller compensation for better frequency response with smaller compensation capacitor. The proposed CFA was fabricated and tested with a standard 0.35 mum CMOS process with competitive performance to its Bipolar and BiCMOS counterparts. The active die area is 0.052 mm2. Experiment results show that the CFA exhibits a minimum bandwidth of 4.5 MHz with a variable gain range of 0 to 46 dB, and a power dissipation of 2.18 mW.

[1]  Barry Harvey.  Current feedback opamp limitations: a state-of-the-art review , 1993, 1993 IEEE International Symposium on Circuits and Systems.

[2]  Mohamad Sawan,et al.  An offset compensated CMOS current-feedback operational-amplifier , 1995, Proceedings of ISCAS'95 - International Symposium on Circuits and Systems.

[3]  J. Bales.  A low-power, high-speed, current-feedback op-amp with a novel Class AB high current output stage , 1996 .

[4]  Ivan Koudar.  Variable gain differential current feedback amplifier , 2004, Proceedings of the IEEE 2004 Custom Integrated Circuits Conference (IEEE Cat. No.04CH37571).

[5]  Christofer Toumazou,et al.  A theoretical study of the stability of high frequency current feedback op-amp integrators , 1996 .

[6]  Gaetano Palumbo,et al.  Current-feedback amplifiers versus voltage operational amplifiers , 2001 .

[7]  Phillip E Allen,et al.  CMOS Analog Circuit Design , 1987 .

[8]  Brent Maundy,et al.  Improving the bandwidth gain-independence and accuracy of the current feedback amplifier , 2005, IEEE Transactions on Circuits and Systems II: Express Briefs.