A GaAs HBT monolithic logarithmic IF (0.5 to 1.5 GHz) amplifier with 60 dB dynamic range and 400 mW power consumption

A GaAs/AlGaAs HBT (heterojunction bipolar transistor) monolithic successive-detection logarithmic IF amplifier (SDLA) is described which demonstrates significant reduction in size and power consumption over state-of-the-art Si bipolar and GaAs metal-semiconductor field-effect transistor log amps with comparable dynamic range and IF bandwidth. This work was motivated by electronic warfare channelized receiver applications in which size, power, and cost are key drivers. The GaAs HBT SDLA log amp achieves single-chip (1.2*2.4 mm/sup 2/) dynamic range greater than 60 dB (-55 to +5 dBm) with less than +or-1-dB error over 1-GHz IF bandwidth at temperatures up to 125 degrees C while consuming less than 400 mW of power.<>