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Photomultiplier-tubes read-out chip



MAROC 3A is a 64-channel front-end ASIC designed to readout negative fast input current pulses such as those provided by Multi Anode Photo Multipliers. Each channel provides a 100% trigger rate for signal greater than 1/3 photoelectron (50fC) and a charge measurement up to 30 photoelectrons (~ 5 pC) with a linearity of 2%. The gain of each channel can be tuned between 0 and 4 thanks to an 8 bit variable gain preamplifier allowing to compensate the non- uniformity between detector channels. A slow shaper combined with two Sample and Hold capacitors allows storing the charge up to 5 pC as well as the baseline. In parallel, 64 trigger outputs are obtained thanks to two possible trigger paths: one made of a bipolar or unipolar fast (15 ns) shaper followed by one discriminator for the photon counting and one made with a bipolar fast shaper (with a lower gain) followed by a discriminator to deliver triggers for larger input charges (> 1 pe). The discriminator thresholds are set by two internal 10-bit DACs. A digital charge output is provided by an integrated 8, 10 or 12 bit Wilkinson ADC.

TRL Technology Readiness Level 9 - Full system running ASIC , reliability proven
Available versions
  • Maroc 3a : available
  • Maroc 3 : discontinued
Detector Read-Out  MAPMT, SiPM
Number of Channel 64
Signal Polarity Negative
Sensitivity Trigger on 1/3 photo-electron or 50fC with a 10PM gain
Timing Resolution 

60ps RMS on single photo-electron, threshold 1/3 of photo-electron

Dynamic Range 5 pC (106 PM gain), Integral Non Linearity : 2% up to 5 pC
Packaging & Dimension 
  • PQFP240
  • TFBGA 353 12x12mm
Power Consumption

3.5 mW/ch, power supply=3.5V

Inputs 64 currents inputs
  • 64 trigger outputs
  • OR of the 64 triggers for each of the 2 discriminators
  • 1 multiplexed analog charge output
  • 1 digital charge measurement (8, 10, or 12 bits)
Internal Programmable Features
  • Gain adjustment between 0 and 2 over 8 bits for each input preamp
  • Trigger threshold adjustment (10bits)
  • Analog and digital charge measurement
  • 64 trigger masks
Evaluation systems
  • Evaluation board : Available - 64 channels


Photomultiplier-tubes read-out chip