huayuliang 发表于 2012-1-13 12:48:25

EDN DesignIdea 上的《Build an op amp with three discrete transistors》的仿真—

好久没看DesignIdea了.....

虽说没少仿真过分立元件搭建的运放，不过这个电路还是让我想仿真下，看看性能如何，结果.....

原文地址：http://www.edn.com/article/520186-Build_an_op_amp_with_three_discrete_transistors.php

Build an op amp with three discrete transistors

This simple ac-coupled design inverts, runs off a single supply, and is self-biasing.
Lyle Russell Williams, St Charles, MO; Edited by Paul Rako and Fran Granville -- EDN, December 1, 2011

You can use three discrete transistors to build an operational amplifier with an open-loop gain greater than 1 million (Figure 1). You bias the output at approximately one-half the supply voltage using the combined voltage drops across zener diode D1, the emitter-base voltage of input transistor Q1, and the 1V drop across 1-MΩ feedback resistor R2.

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Build an op amp with three discrete transistors figure 1Resistor R3 and capacitor C1 form a compensation network that prevents the circuit from oscillating. The values in the figure still provide a good square-wave response. The ratio of R2 to R1 determines the inverting gain, which is −10 in this example.

You can configure this op amp as an active filter or as an oscillator. It drives a load of 1 kΩ. The square-wave response is good at 10 kHz, and the output reduces by 3 dB at 50 kHz. Set the 50-Hz low-frequency response with the values of the input and the output capacitors. You can raise the high-frequency response by using faster transistors and doing careful layout.

http://cache.amobbs.com/bbs_upload782111/files_50/ourdev_712830NWJ0L5.png
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交流分析：
http://cache.amobbs.com/bbs_upload782111/files_50/ourdev_712831N7C4NC.png
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以下为谐波失真分析的设置及曲线：
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http://cache.amobbs.com/bbs_upload782111/files_50/ourdev_712833YV2Z44.png
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http://cache.amobbs.com/bbs_upload782111/files_50/ourdev_712834L9SJUA.png
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chewy 发表于 2012-1-13 13:00:20

沙发支持~

cyberjok 发表于 2012-1-16 21:43:40

值得花时间看看MicroCap手册，本想找找有没有出什么手册或书之类的。。。
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