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Scientific instrumentation SiPM read-out chip



Citiroc 1A is a 32-channel front-end ASIC designed to readout silicon photo-multipliers (SiPM) for scientific instrumentation application.
Citiroc 1A allows triggering down to 1/3 pe and provides the charge measurement with a good noise rejection. Moreover, Citiroc 1A outputs the 32-channel triggers with a high resolution timing (better than 100 ps).
An adjustment of the SiPM high-voltage is possible using a channel-by-channel DAC connected to the ASIC inputs. That allows a fine SiPM gain and dark noise adjustment at the system level to correct for the non-uniformity of SiPMs. CITIROC 1A can be calibrated using a unique calibration signal.
Timing measurement better than 100 ps RMS jitter is measured on single photo-electron along with 1% linearity energy measurement up to 2500 p.e. The power consumption is 225mW/ASIC when all stages are ON.

TRL Technology Readiness Level  8 - Full system using ASIC running - learn more
Available versions
  • Citiroc 1 : discontinued
  • Citiroc 1A : available
Detector Read-Out  SiPM, SiPM array
Number of Channel 32
Signal Polarity Positive
Sensitivity Trigger on 1/3 photo-electron
Timing Resolution   better than 100ps RMS on single photo-electron 
Dynamic Range 0-400 pC i.e 2500 photo-electrons @ 106 SiPM gain
Packaging & Dimension 
  • TQFP 160 28x28mm
  • TFBGA 353 12x12mm
Power Consumption

225 mW when all stages on - supply voltage 3.3V

Inputs 32 voltage inputs with independant SiPM HV adjustments
  • 32 trigger outputs 
  • 2 multiplexed charge output
  • 2 ASIC trigger output (Trigger OR)
Internal Programmable Features
  • 32 HV adjustment for SiPM (32*8bits)
  • Trigger Threshold Adjustment (10bits)
  • Channel by channel gain tuning
  • 32 Trigger Masks
  • Trigger Latch
  • Internal temperature sensor
Evaluation systems