Two CMOS Current Feedback Operational Amplifiers

Two internally compensated CMOS current-feedback operational amplifiers are discussed in this paper. The circuits are entirely made up of class AB stages, thereby increasing slew rate and drive capability, avoiding many of the drawbacks incurred by previous CMOS and even bipolar implementations. Experimental results on one prototype fabricated in a 0.35-mum process using a 20-pF load and supplied with 3.3 V are also given, showing, as main performance parameters, a SR of 35 V/mus and a constant closed-loop bandwidth (in inverting configuration with a 10-kOmega feedback resistor) of about 2 MHz.