A low power flash ADC system with fast data compressor ASIC for a balloon-borne experiment

A low power multi-channel flash ADC system with fast data compressor ASIC (Application Specific Integrated Circuit) was developed for readout of drift chambers on a balloonborne cosmic-ray superconducting spectrometer. The FADC system consists of up to 20 FADC modules, each of which has 32 input channels, and one interface module called crate controller. Each readout channel is equipped with a 30 Msps 8-bit flash ADC and a data compressor ASIC. The data compression is executed synchronously with the analog-to-digital conversion, thereby the compressed data get ready for event building at practically the same time of the end of the digitization. Thus both the event data size and the deadtime of the data acquisition are reduced, and the data of as many events as possible can be recorded onto a limited volume of a storage device on the balloon-borne apparatus. The main logic circuits of the interface module consist of one FPGA, the functions can he changed flexibly according to the demands. The system is powered by batteries and a special care is paid to reduce the power consumption.