Frequency Compensation Design of Three-Stage CMOS OTA Amplifier for RTD Applications

In this paper, a new three-stage CMOS operational transconductance amplifier (OTA) for RTD applications is proposed. The presented structure eliminates the feedforward path and strengthens the feedback path of compensation network together. In addition, the presented circuit uses only a small compensation capacitor on the order of 1 pF, which alleviates the chip area. The circuit is simulated using a 0.18-μm N-well CMOS technology process showing high performance and power efficiency regarding to figure of merit (FOM) factors defined in the literature. The frequency response of the proposed amplifier shows that the DC gain is about 120 dB and bandwidth is 18.8 MHz with a phase margin of 88° and power dissipation of 544 μW.