High-speed GaAs operational amplifier

An operational amplifier has been designed and fabricated using GaAs MESFETs. This amplifier is a general-purpose monolithic GaAs op amp designed as as a stand-alone component. The amplifier has a differential input, an open-loop gain in excess of 60 dB, and is internally compensated. The high open-loop gain (60 dB at 100 kHz) was achieved by using gain stages with positive feedback. The op amp incorporates a current-mirror level-shifting stage which allows the op amp to operate over a wide power-supply range (±5-9 V). Previous designs have diodes to achieve level shifting, a practice that precludes operation over a wide supply range. This op amp is a true analog to its silicon counterparts, but it has a higher gain-bandwidth product.