Fast, radiation-hard GaAs CHIGFET op amp

Abstract

A fast, low-noise, operational amplifier is fabricated in an industrial GaAs technology, exhibiting intrinsic radiation hardness in excess of several hundred megarads. The circuit architecture is based on GaAs/AlGaAs CHIGFETs of 1-/spl mu/m channel length. The amplifier is fully monolithically integrated with low-frequency open-loop gain of 10/sup 5/, gain-bandwidth product of 1.5 GHz, DC input offset voltage of 20 mV, slew rate of 760 V//spl mu/s, and power requirements of 30 mW. Its output voltage is linear from -3 V to +3 V within 1% accuracy. A gain of 50 k/spl Omega/ is achieved for operation as a transimpedance amplifier with risetime <5 ns, which would be suitable for a preamplifier for liquid and solid ionization detectors.