A Low-Noise Current Preamplifier in 120NM CMOS Technology

In this paper we discuss the influence of deep-sub-micron CMOS technology on analog circuit design with a special focus on the noise performance and the ability to design low-noise preamplifiers. To point out, why CMOS technology can grow to a key technology in low-noise and high-speed applications, various amplifier stages applied in literature are compared. One, that fits as a current preamplifier for low-noise applications, is the current mirror. Starting from the basic current mirror, an enhanced current preamplifier is developed, that offers low-noise and high-speed operation. The suggested chip is realized in 0.12mum CMOS technology and needs a chip area of 100mum x 280mum. It consumes about l2.1mW at a supply voltage of 1.5V. The presented current preamplifier has a bandwidth of 800MHz and a gain of 44dB. The fields of application for current preamplifiers are, for instance, charge amplifiers, amplifiers for low-voltage differential signaling (LVDS) based point-to-point data links or preamplifiers for photodetectors.