An ultra-low current mode amplifier aiming at biosensor applications
Recently, along with the booming of research and production of CMOS integrated bio-sensing system (IBS), ultra-low current mode amplifier (UCMA) which servers for biosensor signal pre-amplification implemented in modern CMOS technology is in high demand in areas like ultra-low bio-current analysis and detection, DNA probing and surveying system and etc. In this paper, a novel UCMA module has been presented and verified by SMIC 0.18 mum CMOS process by elaborately considering gain, bandwidth, stability, noise, DC operating point optimization, as well as offset cancellation. Theoretical calculation, HSPICE simulation, and xCalibre post simulation show that the proposed UCMA can stably provide a current gain of 57.6 dB and 3 dB bandwidth of 4.38 MHz with only InA of DC quiescent current, while the input offset current and noise current are less than 22.8 fA and 66.9 fA /radicHz, respectively.