Design and fabrication of a GaAs monolithic operational amplifier

The design and fabrication of the GaAs monolithic operational amplifier are described. The DC gain and frequency characteristics are discussed in detail using an equivalent circuit. The experimentally fabricated chip exhibited a unity-gain frequency of 150 MHz, an open-loop gain of 48 dB, and a common-mode rejection ratio of 63 dB. The amplifier has wide applications in high-speed D/A (digital-to-analog) converter circuits and switched-capacitor filters for video signals.<
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