A wide dynamic range charge integrating analog to digital converter with FASTCAMAC readout

The design and performance of a FASTCAMAC gated charge integrating ADC is presented. A high performance charge to time converter (LeCroy MQT300) is coupled with a time digitizer (LeCroy MTD133) to produce a fast converting, wide dynamic range ADC module. The total dynamic range is greater than 17 bits, in three overlapping 12 bit ranges. The smallest LSB is less than 25 fC and the full scale is greater than 6 nC. A sliding scale is implemented in the time domain, to reduce the differential non-linearity of the time digitizer. The dead time is 5.5 microseconds in auto range mode. The FASTCAMAC readout is capable of a maximum rate of 100 nS per ADC measurement (30 Mbytes/sec)