A silicon-photomultiplier readout integrated circuit for highly granular imaging calorimetry

The KLauS ASIC is a 36-channel mixed-mode silicon-photomultiplier (SiPM) charge readout integrated circuit dedicated to the application in a highly granular imaging calorimeter at a future linear collider experiment. The high density of readout channels together with the dense structure of the calorimeter system limit the readout electronics power consumption down to 25 $\mu$W per channel. This ASIC is designed to read out the SiPM signals with high precision and over a large dynamic range with high linearity. Each channel consists of an analog front-end for charge integration and a 10/12-bit ADC to digitize the pulse height information. The design of the ASIC and results of the characterization measurements will be presented. In addition, the integration of the ASIC into the AHCAL calorimeter prototype of the CALICE collaboration is ongoing and the status will also be reported. Furthermore, a 200 ps bin-sized TDC has been designed for the next version of the KLauS chip, which is implemented to digitize the timing information for the arriving signals. This will allow to study the time development of hadronic showers in the calorimeter with sub-nanosecond resolution.