High-performance CMOS current feedback operational amplifier

The higher speed exhibited by the current-feedback opamp, compared to conventional architectures, is mainly due to the superior slew-rate, whereas the constant closed-loop bandwidth relies on a low input resistance value. This last requirement was revealed as the principal obstacle to the development of efficient CMOS implementations. A high-performance and robust CMOS current-feedback operational amplifier is proposed in this paper. It is obtained through a feedback configuration, which provides low input resistance and, working in class AB, allows high slew-rate capability. A design using a 0.35-/spl mu/m process is given and SPICE simulations confirming the overall good performance are also provided.