DC to 40 GHz broad-band amplifiers using AlGaAs/GaAs HBT's

Abstract

In this paper, we report two types of broad-band amplifiers implemented with AlGaAs/GaAs HBT's. One is a Darlington feedback amplifier and the other is a transimpedance amplifier. In the former circuit, a DC gain of 9.5 dB and a -3 dB bandwidth of 40 GHz were achieved. In the latter circuit, a transimpedance gain of 50 dB/spl Omega/ and a -3 dB bandwidth of 27 GHz were achieved. To our best knowledge, they are the highest speed in each circuit configuration.