Abstract
The purpose of our research is using the CMOS differential pair to design a simplified circuit that not only tallies with the requirement of signal process circuit but also keep the function of gain and bandwidth as common amplifier. Instead of the common amplifier’s complex function, it can reduce the power dissipation loss and easier than operational amplifier. Therefore, the function of amplifier that we use the CMOS differential pair to designed is in the following: open-loop gain 56dB, is 13KHz, the power dissipation is 26uw, input resistance is, output resistance is, CMRR is 106dB, bias current is,supply voltage is, gain-bandwidth product is 8 M. We use it to be the main function of preamplifier and linear amplifier of signal process amplifier. By the way, the characteristics of the output is that closed-loop gain is 63dB, fL=14KHz, fH=76KHz, the output resistance is, the loss of power is 72.2uw, those characteristics will be evaluated the CMOS to replace the BJT.