Design of a Pipeline ADC for the MAPS of China Hyper-Nuclear Spectrometer

Abstract

As the leading research platform of heavy-ion science in China, the physics and applications at the Heavy Ion Research Facility in Lanzhou (HIRFL) and the High-Intensity Heavy-Ion Accelerator Facility (HIAF) drive the development of new detector technology. The China Hyper-Nuclear Spectrometer (CHNS) is a planned all-silicon detector complex at HIAF that will study the hypernuclei with high statistics. A monolithic active pixel sensor (MAPS) is being designed in a 130-nm process for CHNS. This MAPS can measure the energy deposition, the hit position, and the arrival time of the particle hit. As the critical component of this MAPS, a 14-bit 40-Ms/s pipeline analog-to-digital converter (ADC) converts the analog signal from each region of pixels into digital data. It adopts the structure of sample-and-hold amplifier (SHA)-less and a first stage of 3.5-bit. In addition, bootstrapped switches, gain-boosting amplifiers, and the redundancy algorithm have been used in the design to improve conversion accuracy. This ADC has a power consumption of 138 mW and an area of $1380 \times 1300 \; \mu $ m. The test results indicate that it has an effective number of bits (ENOBs) and is 12.19-bit while working at 40 Ms/s.