Flexible Readout Electronics for Monolithic Active Pixel Sensors Characterization

Monolithic Active Pixel Sensors are becoming increasingly attractive as charge particle tracking devices for the next generation of High Energy Physics experiments. For this reason several RD activities are ongoing in different laboratories to improve the performance of conventional monolithics in terms of signal to noise ratio and radiation tolerance. Those improvements come both from the use of different technologies and materials and from the optimization of the front-end electronics. In this context, technologies which allow simultaneous integration of analog and digital electronics in the same pixel are also increasingly exploited.Here, a versatile readout electronics has been specifically developed for a detailed characterization of MAPS with an expected depletion depth of more than 30 \mu \mathrm {m}. Different silicon substrates have been explored to achieve the best performance. The ASIC prototype has been fabricated in 0.11 \mu \mathrm {m} CMOS technology with a die area of 2 \times 2 mm 2 and a low voltage operation of 1.2 V. The test chip consists of a matrix of 24 \times 24 pixel units organized in 4 independent sectors and an End of Column logic. The in-pixel electronics fits an area of 30 \times 30 \mu \mathrm {m}^{2} and it is therefore suitable to develop compact monolithic pixels of 40 \times 40 \mu \mathrm {m}^{2} or more. The strong point of such readout system is the flexibility which allows to get a low power consumption, a very easy scalability and a good adaptability for both sensor polarities. Hereafter, the front-end electronics is described and detailed tests obtained on a first submission presented.