33 GHz monolithic cascode AlInAs/GaInAs heterojunction bipolar transistor feedback amplifier

Implemented with 70-GHz f/sub max/, 90-GHz f/sub tau / AlInAs/GaInAs devices, 8.6-dB gain and DC 33-GHz bandwidth were attained for a monolithic active-biased cascode bipolar feedback amplifier. Because of the significant collector-base feedback time constant, the cascode configuration provides a large improvement in amplifier bandwidth, but a low-impedance bias node must be provided for the common-base transistor. An active bias network was thus used. The resulting 33-GHz amplifier bandwidth (and predicted noise figure) is competitive with AlGaAs/GaAs MODFET travelling-wave amplifiers, but with a much smaller die area (excluding bond pads) of 200 mu m*225 mu m. The AlInAs/GaInAs monolithic feedback amplifiers are extremely small, wideband gain blocks suitable for use as subcomponents in complex MMICs and MIMICs.<
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