反馈式电压放大器增益与带宽相关性系统分析

The Interrelation of Gain and Bandwidth of Feed-back Voltage Amplifiers

对用四种运放作开环元件的反馈式电压放大器的增益与带宽相关性作系统分析，结果表明：传统电压型运放闭环电压放大器的增益一带宽积为常数；其它三种运放闭环电压放大器的增益与带宽相互独立，带宽可在增益改变下保持常数；环增益对增益与带宽相关性有重要作用。SPICE模拟结果验证了理论分析的正确性。

The interelation property of gain and bandwidth of feed--back voltage amplifiersare systematically analyzed. Thhe results show that the constant gain-bandwidth product isvalid only for the closed--loop voltage amplifier formed by traditional voltage OP-AMP; thebandwidth of voltage amplifier formed by other three types OP--AMP is independent on voltagegain$the loop gain is a determinative factor on the interrelation of gain and bandwidth. Theanalyzed results are verified by SPICE simulation results.