论文信息 - An approach to test the open-loop parameters of feedback amplifiers

An approach to test the open-loop parameters of feedback amplifiers

A novel method for determining open-loop parameters, such as unity-gain frequency and phase margin, in feedback amplifiers is given. It is based on relations between open-loop and closed-loop configurations and is very useful for evaluating the above parameters in a unity-gain amplifier from a simple measure of its closed-loop 3 dB cutoff frequency and the respective phase for a given feedback factor /spl beta/. The approach is validated by simulations of an ideal amplifier and of a real OTA. Moreover, measures carried out for a /spl mu/A-741 operational amplifier show a percentage error between real and calculated values lower than 2%.

Gaetano Palumbo | Gianluca Giustolisi

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

[2] G. Palumbo,et al. A novel representation for two-pole feedback amplifiers , 1998 .

[3] A. Carlosena,et al. On the experimental methods to characterize the opamp response: a critical view , 1996 .

[4] Willy M. C. Sansen,et al. Measurement of Operational Amplifier Characteristics in the Frequency Domain , 1985, IEEE Transactions on Instrumentation and Measurement.

[5] S. Natarajan. A simple method to estimate gain-bandwidth product and the second pole of the operational amplifiers , 1991 .

[6] G. Temes,et al. Analog MOS Integrated Circuits for Signal Processing , 1986 .

[7] G. Palmisano,et al. 1.2-V CMOS op-amp with a dynamically biased output stage , 2000, IEEE Journal of Solid-State Circuits.

[8] G. Palmisano,et al. Analysis and compensation of two-pole amplifiers with a pole-zero doublet , 1999 .

[9] Robert G. Meyer,et al. Analysis and Design of Analog Integrated Circuits , 1993 .

[10] Gaetano Palumbo. Bipolar Current Feedback Amplifier: Compensation Guidelines , 1999 .

[11] Gaetano Palumbo,et al. A 1.5-V high drive capability CMOS op-amp , 1999 .

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

[13] K. Martin,et al. On the stability of the phase-lead integrator , 1977 .

[14] S. S. Awad. A simple method to estimate the ratio of the second pole to the gain-bandwidth product of matched operational amplifiers , 1990 .