An lpGBT subsystem for environmental monitoring of experiments

Abstract

In this paper, the Low Power Giga Bit Transceiver (lpGBT) built-in system for environmental monitoring of the LHC experiments is presented. Eight external analogue inputs and eight internal voltages are multiplexed into an instrumentation amplifier with selectable gain, whose output is digitised by a 10-bit SAR ADC. A programmable current source can be enabled for each external input to implement resistance measurements. Internal channels are used to monitor power supplies and the output of the temperature sensor. The environmental monitoring system includes a precise 1 V reference voltage source and a 10-bit voltage DAC. All blocks were designed and fabricated in 65 nm CMOS technology, fully characterised, and the pre- and post-irradiation measurement results are presented in this work.