Circuit design and verification for ultra low current sensing amplifier aimed at bio-sensor applications

It has become increasingly apparent that ultra low current sensing amplifiers (LCSA) play a critical role in many sensor applications, especially for bio-sensing systems. The challenging tasks in LCSA design include achieving adequate performance in gain, noise, and stability, and the integration with sensor array on a single chip. In this paper, two CMOS LCSA circuits are described with current sensitivity in the range of pico-ampere. The detailed design considerations are discussed and simulated results which verify the design are presented