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| university:courses:electronics:text:chapter-11 [20 Aug 2017 11:45] – Doug Mercer | university:courses:electronics:text:chapter-11 [14 Sep 2018 19:59] – spelling correction Daud Zoss |
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| ====11.4.1 Mirror Gain other than 1==== | ====11.4.1 Mirror Gain other than 1==== |
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| If transistors Q<sub>1</sub> and Q<sub>2</sub> in figure 11.4 are identical (that is have the same size emitter and thus equal I<sub>S</sub>) the input current to output current ratio or gain is ideally 1. There are often occasions when a gain other than one is required. When building circuits from discreet devices only simple integer ratios are possible while in microelectronic integrated circuits it is possible to make transistors with arbitrary emitter areas, A. However, even in integrated circuits the best design practice is to use identical unit size transistors when making current mirrors. | If transistors Q<sub>1</sub> and Q<sub>2</sub> in figure 11.4 are identical (that is have the same size emitter and thus equal I<sub>S</sub>) the input current to output current ratio or gain is ideally 1. There are often occasions when a gain other than one is required. When building circuits from discrete devices only simple integer ratios are possible while in microelectronic integrated circuits it is possible to make transistors with arbitrary emitter areas, A. However, even in integrated circuits the best design practice is to use identical unit size transistors when making current mirrors. |
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| {{ :university:courses:electronics:text:chptr11-f5.png?600 |}} | {{ :university:courses:electronics:text:chptr11-f5.png?600 |}} |
