A CMOS op-amp input and gain stage suitable for low voltage operation are introduced. The input stage operates in strong inversion and has common-mode range beyond rail-to-rail. It uses two complementary differential pairs connected in parallel. The common-mode dependent current biasing employs only four transistors, does not require additional voltage references, current switches and/or current mirrors and does not increase the minimum required supply voltage. The variation of the net transconductance is approximately 15% over the entire common-mode range. The gain-stage has constant output resistance. In addition it reduces the variation of the net transconductance due to variations in /spl mu//sub n///spl mu//sub p/ ratio.
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机译：介绍了适用于低压操作的CMOS运算放大器输入和增益级。输入级具有强大的反相能力，并具有超出轨到轨范围的共模范围。它使用两个并联的互补差分对。依赖于共模的电流偏置仅采用四个晶体管，不需要额外的参考电压，电流开关和/或电流镜，也不会增加所需的最小电源电压。在整个共模范围内，净跨导的变化约为15％。增益级具有恒定的输出电阻。另外，由于/ spl mu // sub n /// spl mu // sub p /比率的变化，它减少了净跨导的变化。
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