Design and optimization of operational amplifiers for SC systems - a comparative study in CMOS 0.18 µm, 0.35 µm, and 0.8 µm technologies

Design and optimization of a simple but efficient operational amplifier (OA) for switched-capacitor finite impulse response (SC FIR) filters are presented. The main design criteria are: proper characteristics for application in SC FIR filters, simplicity of the circuit structure, the area in the silicon realization and low power dissipation. The OAs have been realized in three different CMOS technologies, namely AMS 0.8 µm and 0.35 µm as well as TSMC 0.18 µm, for comparison. The best performance has been achieved in the 0.18 µm process, as expected. The gain bandwidth product (GBP) equals 1.9 GHz in this case, while the power dissipation 700 µW at 1.8V power supply. The chip area equals 280 µm² that is 40 times less than in case of the 0.8 µm process.