The DRS chip: cheap waveform digitizing in the GHz range

An analog sampling chip is currently under development for fast waveform digitizing of PMT and drift chamber signals for the MEG Experiment at PSI. This experiment searches for the lepton-flavour violating decay μ+→e+γ with a sensitivity down to 10−13. The first prototype of the chip contains 768 capacitive sampling cells fabricated in a 0.25 μm CMOS process. Sampling takes place with an on-chip generated frequency ranging up to 2.5 GHz. The cells are read out at 40 MHz with an external 12 bit flash ADC. The design of the chip is described and test results from the first prototype are reported.