AMIC: an expandable integrated analog front-end for light distribution moments analysis

Abstract

A current buffer delivers a copy of each input current to several processing blocks. The current preamplifier is designed in order to achieve unconditional stability under high input capacitance, thus allowing the use of both Photo-Multiplier Tubes (PMT) and Silicon Photo-Multipliers (SiPM). Each processing block implements an analog current filtering by multiplying each input current by a programmable 8-bit coefficient. The latter is implemented through a high linear MOS current divider ladder, whose high sensitivity to variations in output voltages requires the integration of an extremely stable fully differential current collector. Output currents are then summed and sent to the output stage, that provides both a buffered output current and a linear rail-to-rail voltage for further digitalization. Since computation is purely additive, the 64 input channels of AMIC do not represent a limitation in the number of the detector's outputs. Current outputs of various AMIC structures can be combined as inputs of a final AMIC, thus providing a fully expandable structure. In this version of AMIC, 8 programmable blocks for moments calculation are integrated, as well as an I2C interface in order to program every coefficient. Extracted layout simulation results demonstrate that the information provided by moment calculation in AMIC helps to improve tridimensional positioning of the detected event. A two-detector test-bench is now being used for AMIC prototype characterization and preliminary results are presented.

Estudio e implementación de algoritmos digitales para la mejora de la resolución temporal en sistemas de tomografía por emisión de positrones

“…Para la etapa integrada, el grupo de investigación en el que se ha desarrollado este trabajo ha propuesto dos aproximaciones distintas dando lugar a dos circuitos integrados diferentes: PESIC [56], [57] y AMIC [58], [59], [60]. Las dos tecnologías se encargan de reducir el número de señales analógicas de los 64ánodos de corriente que proporciona el PMT.…”

“…Las señales del PSPMT de cada uno de los detectores son transformadas mediante un ASIC de procesado analógico (PESIC o AMIC) en un número reducido de señales que permiten obtener la posición, energía y la DOI [56,43,58,59].…”

Development of a data acquisition architecture with distributed synchronization for a Positron Emission Tomography system with integrated front-end.

“…This generalization is the main idea behind AMIC [256,257], a front-end ASIC designed at EDNA with 64 current inputs that generates up to 8 current outputs with 8-bit, digitally programmable positive coefficients. Programmability offers great flexibility in the usage of the circuit.…”