A 15μW 12-bit dynamic range charge measuring front-end in 0.13μm CMOS

A 100 μm × 100 μm readout cell with a power consumption of 15 μW and optimized for 12 bits dynamic range is presented. This circuit has been developed to readout the hybrid pixel sensors for the Micro-Vertex Detector (MVD) of the PANDA experiment at GSI. The readout architecture is based on the Time-over-Threshold technique which allows to achieve low-power charge measurement with a high dynamic range. The front-end has been designed to handle input charges up to 100f C. The analog building blocks are described in detail, focusing the attention on the main design challenges: the dynamic range limitation, the implementation of a compact filter for the leakage compensation, and the management of the mismatch effects. A first prototype has been designed and produced in a CMOS 0.13 μm technology and the test results are discussed. Given the very low-power consumption and the small size of the readout cell it is interesting to employ it as a compact digitizer for other applications. Preliminary studies have been done to extend this concept to the readout of double sided strip sensors of the PANDA MVD.