A variable gain amplifier operating at 2.5 GHz based on Single Ended topology has been designed and characterized. Three such stages were cascaded preceded by a single stage LNA. A source follower is used at the output as an active load matching. Overall dynamic gain variation is 45 dB with a maximum gain of 47 dB. The -3 dB bandwidth is 0.800 GHz. A minimum noise figure of 0.81 dB is obtained in the highest gain mode. Maximum value of 1 dB compression at the output is -7.2 dBm and the corresponding third order intercept point is +5.3 dBm. Consumed DC power 285 mW and is immune to gain variation. The circuit is implemented with GaAs pHEMT technology. The combined area occupied by the multistage low noise VGA and the single ended VGA is 3.5 mm X 3 mm.
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机译：已经设计和表征了基于单端拓扑在2.5 GHz下工作的可变增益放大器。三个这样的阶段被级联，之后是单阶段LNA。源跟随器在输出端用作有效负载匹配。整体动态增益变化为45 dB，最大增益为47 dB。 -3 dB带宽为0.800 GHz。在最高增益模式下获得的最小噪声系数为0.81 dB。输出处1 dB压缩的最大值为-7.2 dBm，相应的三阶截点为+5.3 dBm。消耗的直流功率为285 mW，不受增益变化的影响。该电路采用GaAs pHEMT技术实现。多级低噪声VGA和单端VGA的总面积为3.5 mm X 3 mm。
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