Low-voltage CMOS current amplifier and its use for high-performance voltage amplification

A CMOS current operational amplifier (COA) is exploited to obtain a voltage amplifier operating at 1 V and with an input bias voltage of 0.5 V. The COA employs a class AB input stage that enhances the slew-rate performance and provides accurate control of both the quiescent currents and the input bias voltage. It exhibits a 56 dB loop gain with a gain-bandwidth product of 18 MHz. Based on this COA, a 1-V voltage amplifier is implemented. It provides a constant closed-loop bandwidth of about 2 MHz and exhibits a THD better than -60 dB for a 1 MHz 600 mV_pp output signal.