CMOS Rad-Hard Front-End Electronics for Precise Sensors Measurements

This paper reports a single-chip solution for the implementation of radiation-tolerant CMOS front-end electronics (FEE) for applications requiring the acquisition of base-band sensor signals. The FEE has been designed in a 0.35μm CMOS process, and implements a set of parallel conversion channels with high levels of configurability to adapt the resolution, conversion rate, as well as the dynamic input range for the required application. Each conversion channel has been designed with a fully-differential implementation of a configurable-gain instrumentation amplifier, followed by an also configurable dual-slope ADC (DS ADC) up to 16 bits. The ASIC also incorporates precise thermal monitoring, sensor conditioning and error detection functionalities to ensure proper operation in extreme environments. Experimental results confirm that the proposed topologies, in conjunction with the applied radiation-hardening techniques, are reliable enough to be used without loss in the performance in environments with an extended temperature range (between -25 and 125 °C) and a total dose beyond 300 krad.

I. Introduction

The front-end electronics (FEE) is a very common element in space, high energy physics and nuclear applications. This circuitry performs functions for sensor-signal conditioning, analogue-to-digital conversion (ADC), and interfacing with the higher levels of the system, but also has to be capable of overcoming the extreme environmental conditions, in terms of radiation and extended operating temperature range, while maintaining the performance. This implies the use of robust solutions and additional functionalities, like temperature monitoring, error detection or on-flight calibration functions [1].