A monolithic 24.9 GHz limiting amplifier using 0.2 mu m-AlGaAs/GaAs-HEMTs

A monolithic limiting amplifier for high-speed communication systems has been fabricated using a 0.2 mu m enhancement / depletion AlGaAs/GaAs-HEMT (integral of tau = 60 / 55 GHz) technology. As a limiting amplifier, the circuit has a bandwidth of 24.9 GHz with a gain of 16 dB for an input power of -25 dBm. For applications as a linear amplifier, it has a bandwidth of 19.2 GHz with a gain of 26 dB for an input power of -50 dBm. Performance at a data bit rate of 25 Gb/s for single-ended input was obtained. The circuit features a differential configuration with accoupled active source followers to increase frequency band. The power consumption is 600 mW using a single supply voltage of -3.5 V.