1 Second generation Front-end chip for H-Cal SiPM readout : SPIROC Réunion EUDET France – LAL – jeudi 5 avril 2007 M. Bouchel, F. Dulucq, J. Fleury, C. de La Taille, G. Martin-Chassard, L. Raux LAL Orsay IN2P3-CNRS – Université Paris-Sud – B.P. 34 – Orsay cedex – France

2 First generation chip for SiPM : short reminder (1/1)  18-channel 8-bit DAC (0-5V)  18-channel front-end readout :  Variable gain charge preamplifier (0.67 to 10 V/pC)  Variable tine constant CRRC 2 shaper (12 to 180 ns)  Track and hold  1 multiplexed output  Power consumption : ~200mW (supply : 0-5V)  Technology : AMS 0.8 m CMOS  Chip area : ~10mm ²  Package : QFP-100

3 First generation chip for SiPM : Short reminder (2/2) M.Groll and A. Karakash DESY / MEPhI Measured by LAL group at Orsay Single photoelectron spectra

4 Second generation chip for SiPM : SPIROC - A-HCAL read out - Silicon PM detector - 36-channel prototype - Compatible with new DAQ - Many SKIROC, HARDROC, and MAROC features re-used SPIROC submission expected on 11 th june Skiroc layout : ~20mm² Technology : AMS 0.35 m SiGe

5 SPIROC main features  36-channel readout chip  Internal input 8-bit DAC (0-5V) for SiPM gain adjustment  Energy measurement : 2 gains / 12 bit ADC 1 pe  2000 pe Variable shaping time from 50ns to 100ns pe/noise ratio : 11  Time measurement : 1 TDC (12 bits) step~100 ps pe/noise ratio on trigger channel : 24 Fast shaper : ~15ns Auto-Trigger on ½ pe  Analog memory for time and charge measurement : depth 16  Power pulsing integrated  Low consumption : ~25µW per channel (in power pulsing mode)  Calibration injection capacitance  Embedded bandgap for voltage references  Embedded DAC for trigger threshold  Compatible with physic prototype DAQ Serial analogue output External “force trigger”  Probe bus for debug  12-bit Bunch Crossing ID  SRAM with data formatting 2 x 2kbytes = 4kbytes  Output & control with daisy-chain

6 SPIROC : One channel schematic IN test

DAQ ASIC Chip ID register 8 bits gain Trigger discri Output Wilkinson ADC Discri output gain Trigger discri Output Wilkinson ADC Discri output..… OR36 EndRamp (Discri ADC Wilkinson) 36 TM (Discri trigger) ValGain (low gain or high Gain) ExtSigmaTM (OR36) Channel 1 Channel 0 ValDimGray 12 bits … Acquisition readout Conversion ADC + Ecriture RAM RAM FlagTDC ValDimGray 12 8 ChipID Hit channel register 16 x 36 x 1 bits TDC ramp StartRampTDC BCID 16 x 8 bits ADC ramp Startrampb (wilkinson ramp) 16 ValidHoldAnalogb RazRangN 16 ReadMesureb Rstb Clk40MHz SlowClock StartAcqt StartConvDAQb StartReadOut NoTrig RamFull TransmitOn OutSerie EndReadOut Chipsat

8 Block scheme of SPIROC Bunch crossing Ch. 0 Ch. 1 Analog channel Analog mem. 36-channel 12-bit Wilkinson ADC for charge and time measurement Analog channel Analog mem. Ch. 35 Analog channel Analog mem. 12-bit counter Time digital mem. Event builder Memory pointer Trigger control Main Memory SRAM Com module HCAL SLAB

9 SPIROC : Photoelectron response simulation High gain Preamplifier response Low gain Preamplifier response Fast shaper High gain Slow shaper Low gain Slow shaper Tp=15ns Tp=50ns Noise/pe ratio = 25 Noise/pe ratio = 11 Noise/pe ratio = 3 1mV/pe 10mV/pe 120mV/pe Simulation obtained with SiPM gain = 10 6 _ 1 pe = 160 fC

10 SPIROC : RAM Mapping Charge Measurement Time Measurement x36 Time stamp (BCID) Chip ID (8 bits) Time stamp (12 bits) TDC measurement (12 bits) ADC measurement (12 bits) Gain (1 bit) Hit (1 bit) TDC measurement (12 bits) Time stamp (12 bits) TDC measurement (12 bits) ADC measurement (12 bits)

11 SPIROC : Acquisition mode  Store up to 16 events in RAM  Stop acquisition when ram_full signal asserted Common collector bus for ram_full signal 36

12 SPIROC : Readout mode  Based on daisy chain mechanism initiated by DAQ Possibility to bypass a chip by slow control  One data line activated by each chip sequentially Readout rate few MHz to minimize power dissipation With 500 pF bus capacitance, power dissipation is ~10µW/chip i=CdV/dt = 1 mA => 1 mW for up to 100 chips on bus Readout time max (ram full) 20kbits x 1 µs = 20 ms/chip

13 Time considerations time Time between two trains: 200ms (5 Hz) Time between two bunch crossing: 337 ns Train length 2820 bunch X (950 us) Acquisition 1ms (.5%) A/D conv..5ms (.25%) DAQ.5ms (.25%) 1% duty cycle IDLE MODE 99% duty cycle 199ms (99%) analog detectors only

14 Schedule  First Prototype submission : 11 th june 2007  Expected delivery : September 2007  SPIROC Characterization : End of Year

15 Conclusion  SPIROC designed for SiPM A-HCAL : second generation ASIC  Many SKIROC, HARDROC, and MAROC features re-used for SPIROC : power pulsing, bandgap, daisy chain mechanism, etc.  New features embedded : Time measurement, low consumption input DAC, etc.  Compatible with new DAQ  Complexity is increasing  Layout in progress : Submission in june 2007 and first prototype expected in September 2007