25 Gb/s AGC amplifier, 22 GHz transimpedance amplifier and 27.7 GHz limiting amplifier ICs using AlGaAs/GaAs-HEMTs

Abstract

Automatic-gain-control (AGC), transimpedance, and limiting amplifiers are key elements in optical-fiber links and measuring equipment. This AGC amplifier and transimpedance amplifier are based on 0.3 /spl mu/m gate length HEMTs (f/sub T/=50 GHz). The limiting amplifier uses 0.2 /spl mu/m gate length (f/sub T/= 60 GHz) enhancement (e-mode) and depletion (d-mode) AlGaAs/GaAs HEMTs. The AGC amplifier has 18 GHz bandwidth and 30 dB maximum differential gain with 35 dB dynamic range. The transimpedance amplifier has 22 GHz bandwidth with 76 dB/spl Omega/ gain and the limiting amplifier has 27.7 GHz bandwidth with 26 dB differential gain.