A 3.2 GHz 26 dB wide-band monolithic matched GaAs MESFET feedback amplifier using cascodes

Feedback around cascode stages is demonstrated to be a useful means of making matched direct coupled amplifiers with higher bandwidths than afforded by conventional common-source topologies. Design techniques are described for an amplifier which is capable of operation to DC and which exhibits a measured gain of 26 dB, a 3.2 GHz bandwidth, and a 2.5:1 VSWR in a 1- mu m GaAs MESFET process. A novel adjustment scheme is introduced whereby the amplifier's frequency response can be modified using a DC bias voltage to ensure stable circuit operation in spite of MESFET modeling inaccuracies and GaAs processing variations.<
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