Design Of A Signal Generator Using Current Feedback Operational Amplifiers

Abstract

Sinusoidal, triangular and rectangular waveforms are generated using current feedback operational amplifiers. A signal generator using a Current Feedback Operational Amplifier (CFOA) was designed, simulated and fabricated. The simulated frequency of oscillation for the sinusoidal wave is 13.13 MHz to 23.94 MHz, for the triangular and the rectangular wave are 6.78 MHz to 59.5 MHz in simulation. The current feedback operational amplifier can achieve higher oscillation frequency than a voltage feedback operational amplifier. Two different types of current feedback operational amplifiers were designed. These are the double buffer current feedback operational amplifier and the double buffer current booster current feedback operational amplifier. A macro-model for the double buffer CFOA is developed as well. Although the voltage feedback amplifier has many advantages, the current feedback amplifier can operate at higher frequencies. Three test chips for the current feedback operational amplifier were designed. UTA246V, UTA246W are the double buffer CFOA and UTA246X is double buffer current booster CFOA. A triangular and rectangular wave generator was built using the UTA246W CFOA. The frequency of oscillation was found 2.8 MHz.