MICROROC A MICROMEGAS Readout Chip

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MICROROC

A MICROMEGAS Readout Chip

RD51 mini-week CERN 13-15 June 2012

R. Gaglione

on behalf of the MICROMEGAS DHCAL team (LAPP-LAL-NTUA-IRFU)

Laboratoire d’Annecy-le-Vieux de Physique des Particules,

Universit´e de Savoie, CNRS/IN2P3

FRANCE

13 june 2012

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Outline

Introduction Prototypes tests

Production

Readout and SRS integration

Conclusion

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Outline

Introduction

Prototypes tests

Production

Readout and SRS integration

Conclusion

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Introduction

MICROROC is a 64 channels integrated circuit packaged in TQFP160 intended to be used with MPGD-based DHCAL (MICROMEGAS or GEM).

ˆ MICROROC is the fruit of the collaboration

between LAPP and LAL/OMEGA based on the experience of previous ASICs (DIRAC and HARDROC) and on multiple test beam results

ˆ Same Digital part as HARDROC2b, but charge

preamplifier input stage + sparks protection [R. Gaglione] and slower shaping + 4-bit DAC offset correction per channel [N. Seguin]

ˆ MICROROC is pin a pin compatible with the

HARDROC2b to minimize boards modifications.

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Functioning

MICROROC operation is tight by ILC beam structure requirements, and divided into two main phases.

ˆ During the first phase the beam is on: each channel collect detector signal and compare the charge to the three defined thresholds, then the result is stored inside digital memory if at least one channel as a charge bigger than lowest threshold (auto-trigger mode).

ˆ During the second phase (beam off), the analog part is powered down, and a serial daisy-chained readout is performed.

For beam test operation, an external trigger is available, as well as an analog multiplexed readout for fine detector characterisation.

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Global architecture

multiplexed analog output RAM 24 high gain low gain preamplifier charge 4−bit DAC 10−bit DAC ONE CHANNEL calibration R/W ctrl end readout external trigger start readout discriminators encoder BCID counter RAM full serial output transmit ON 2 low medium high OR

Different kinds of fast triggers are available.

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Characteristics and performances summary

ˆ Technology: AustriaMicroSystem SiGe 0.35µm

ˆ Die size: 4.85×4.3 mm (∼21 mm2)

ˆ Dynamic range: 500 fC

ˆ Preamplifier gain: 2.38 mV/fC

ˆ High gain shaper: 12 mV/fC

ˆ Low gain shaper: 2.87 mV/fC

ˆ Peaking times: 30, 50, 100 and 200 ns

ˆ Cdet: 80 pF (now: Cdet=60 pF)

ˆ Noise rms: 1 fC at preamplifier output, 0.24 fC with 200 ns shaping (@Cdet: 80 pF)

ˆ Minimum threshold: ∼1 fC (MIP Landau MPV @ ∼20 fC)

ˆ Power consumption: 68 mA@3.5 V→240 mW

ˆ Memory: 127 events (64 channels + 24bits BCID@200 ns)

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Outline

Introduction

Prototypes tests

Production

Readout and SRS integration

Conclusion

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Shapers

Setting Measure Simulation Gain Tp Gain Tp (mV/fC) (ns) (mV/fC) (ns) 00 7.6 76.3 10.5 30 01 9.7 114.2 11.0 100 10 9.8 157.4 11.1 150 11 10.2 192.3 11.2 200

Good agreement between simulation and real behaviour.

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Thresholds DAC

For each DAC, the linearity is about 3 DACU.

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Offset correction DAC

The linearity is better than 1 DACU and q=2.8 mV.

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Offset correction

The offset correction allows to divide by 2 the thresholds dispersion inside each chip (thus reducing efficiency disparities of the detector).

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Analog Readout

The analog readout has been tested with muon beam at CERN/SPS. The Landau distribution and the pedestal are clearly separated. This feature isvery importantto calibrate full readout chain and set the 3 threshold with accuracy.

1000 1200 1400 1600 1800 2000 0 20 40 60 80 100 120 140 160 180 200 Constant 202.9Mean 1168 Sigma 4.032 Constant 736.9 MPV 1242 Sigma 32.28

This plot is preliminary!

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Outline

Introduction Prototypes tests

Production

Readout and SRS integration

Conclusion

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Status

Prototypes tests

The chip has been sent in MPW run inJune 2010 and 5 prototypes have been received inSeptember 2010. The behaviour of the prototypes is very satisfaying.

Production 1

After prototypes tests in LAL and LAPP, a reorder has been placed for 350 chips (packaged in TQFP160) inOctober 2010. 341 chips have been received inFebruary 2011.

Production 2

Then, a second production has been ordered inNovember 2011for 830 chips (still in TQFP160).

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Test bench

Three test boards with DIF1 firmware, and controlled by LAPP Labview DAQ. Thus, data are analysed with MICROMEGAS ROOT framework (used to analyse detector data).

1

Data Inter-Face Board: the acquisition board designed at LAPP used to read detectors within CALICE collaboration

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Test procedure

For each channel of each chip (peaking time: 200 ns, pedestal DAC @7):

ˆ Test input bondings (inject to all channels at the same time with an external capacitor);

ˆ Measure pedestals;

ˆ Inject 22.5 fC with internal Ctest vs. threshold.

Then, analyze data off line with MICROMEGAS data analysis framework:

ˆ Verify bonding of each input;

ˆ Plot S-Curve for each charge, for each channel;

ˆ Plot inflexion point of S-Curves vs. input charge;

ˆ Verify gain for each channel (must be nominal ±10 %). 1136 chips have been tested and analysed.

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Test results

Production 1

ˆ Packaging: 341/350 yield 97.4 %

ˆ 4 faulty chips (configuration errors);

ˆ 0 with bad bonding;

ˆ 8 with bad gain;

ˆ 329 OK; Yield: 96.5 %. Production 2 ˆ Packaging: 794/830 yield: 95.6 % ˆ 9 faulty chips;

ˆ 0 with bad bonding;

ˆ 33 with bad gain;

ˆ 753 OK; Yield: 94.7 %.

The LAPP use 600 chips at the moment → some spares are available for the community!

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Gain dispersion

Convertion ratio dispersion, for all channels, @ Tp=200 ns:

Production 1

Constant 1126 Mean 0.1407 Sigma 0.002714

Conversion ratio [fCV/DACu] 0.12 0.125 0.13 0.135 0.14 0.145 0.15 0.155 0.16 Count 0 200 400 600 800 1000 1200 Constant 1126 Mean 0.1407 Sigma 0.002714 Constant 1126 Mean 0.1407 Sigma 0.002714 Mean: 0.14 fC/DAC Sigma: 0.002 fC/DAC Production 2 Constant 2397 Mean 0.1399 Sigma 0.002977

Conversion ratio [fCV/DACu] 0.12 0.125 0.13 0.135 0.14 0.145 0.15 0.155 0.16 Count 0 500 1000 1500 2000 2500 Constant 2397 Mean 0.1399 Sigma 0.002977 Constant 2397 Mean 0.1399 Sigma 0.002977 Mean: 0.14 fC/DAC Sigma: 0.003 fC/DAC

Not gaussian → 3 generators not aligned!

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Outline

Introduction Prototypes tests

Production

Readout and SRS integration

Conclusion

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Overview

MICROROC is designed to be daisy chained without any external circuitry, thanks to open collector output signals.

ASIC 1 ASIC 2 data_out clk− clk+ srout srin sc_out sc_in reset power_on control ram_full ext_trig inj_test analog 50 ohm 100 ohm analog signals signals digital data_out clk− clk+ srout srin sc_out sc_in reset power_on control ram_full ext_trig inj_test analog analog inj_test data_out clk− clk+ reset power_on control ram_full ext_trig sc_in sc_out sroutsrin

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ASU: Active Sensor Unit: top

The PCB hosts 24 chips (1536 channels). A detector (1 m2 is made of 6 ASUs.

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ASU: Active Sensor Unit: bottom

On the other side: the mesh is laid (bulk type) on the 1536 1 cm2

pads.

Dimensions 32×48 cm2.

One spare PCB is available to the communityas well as a gas-tight

test box.

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ASU: complete detector

A detector: 1 m2 is made of 6 ASUs (144 chips).

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CALICE Readout System

DIF DIF CCC TLU DCC DCC Giga−DCC Detector beam info trigger HDMI HDMI DIF Gigabit Eth

DCC: Data Concentrator Board DIF: Detector InterFace

TLU: Trigger and Logic Unit CCC: Clock and Control Card

All boards are 6U and are powered thanks to VME crate. Software: X-DAQ

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DIF Readout with USB

As the whole system CALICE acquisition is not ready yet, an USB readout scheme is used, either with Labview or with XDAQ:

DATA on USB link USB Detector DCC DCC S−DCC DIF DIF DIF beam info trigger HDMI HDMI

Although not elegant, this system works with 150 DIF!

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DIF

The DIF (Detector InterFace boards) handles digital and analog signals, thanks to onboard ADC.

An USB link has been implemented for detector tests and debugging, with a Labview software.

Each DIF manage up to about 150 MICROROC → 3 DIF are used for 1 m2 detector.

Cost: about 200AC (depend on FPGA size, ADC. . . ).

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MICROROC SRS integration

DIF board use HMDI connector with:

ˆ one pair for clock

ˆ one pair for command

ˆ one pair for busy (state)

ˆ one pair for ramfull (state)

It is foreseen to move trigger signal from command to the free wire of HDMI cables.

No hardware development necessary to use MICROROC with SRS?

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Outline

Introduction Prototypes tests

Production

Readout and SRS integration

Conclusion

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Conclusion

MICROROC chip gives very good performances with MICROMEGAS detectors (see WG2 talks at previous RD51 meetings).

But some improvements are already listed:

ˆ Add zero suppression inside ASIC

ˆ Add one TDC per channel (CLIC requirement)

ˆ Allow a better offset correction (reduce DAC bias)

ˆ Add serial number inside PROM

ˆ Add temperature sensor

ˆ I2C-like configuration

A test with a THGEM detector should be performed this year (autumn RD51 test beam).

Any suggestion or request from RD51 collaboration is welcome!

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External protection network

At the moment, an external protection network is used on PCB, to block the remaining surge of spark inside detector. In addition, new protection diodes (Dx) have been included for each channel.

No more dead channels after 3 testbeams.

Cdet Cs D D D2 D1 D3 D4 Rp anode Rs

Rp=1 MΩ, Rs=10 Ω, Cs=470 pF, D are ON-Semiconductor NUP 4114.

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Protection benchmark ASIC

Two savours of power supply pads, 6 kinds of i/o pads for each. Each i/o is connected to a MICROROC CPA.

A dedicated testboard has been designed, to be used with spark generator.

Diodes from CEA Saclay have been packaged to be compatible with this testboard.

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Power supply pads

Each power supply pad set consists in 3 pads: vdd, vsub and gnd

vdd vdd vsub gnd gnd vsub OLD NEW

OLD type is included in MICROROC.

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Input/Output pads

6 kinds of i/o pads for each. Each i/o is connected to a MICROROC PA.

Mainly variation of diode size for 5 inputs, and active protection for 1 input.

io io

No result yet: tests have just started!

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Results with detector

Some great results:

Pedestal correction allows to reach very low bad hit contamination (5 Hz for 9216 channels) in auto-trigger mode.

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Detailed power consumption

Stage Number of stage Stage Consumption Total consumtion (µA) including bias (mA)

Preamplifier 64 850 54.7 Shapers 3×64 53 1.13 Discriminators 3×64 40 7.7 DAC 3 173 0.52 Bandgap 1 1200 1.2 Digital (FSM+RAM) 1 2400 2.4

Digital (Data tranmission) 1 400 0.4

Total 68

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Chip readout

repetition rate: 200 ms (5 Hz)

train length: bunch# x bunch period bunch period (189 ns to 480 ns)

acquisition readout acquisition

PHASE POWER CHIP 1 POWER CHIP 2 BEAM STRUCTURE

POWER CHIP n

There is one serial output which is transferred to the DAQ during the inter bunch. Moreover, during this inter bunch, the transceivers of chip which are not transmitting data are shut down to save power thanks to the POD (Power-On Digital) module. The data format is: depth × (data × channels + BCID + chipID)

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Chip by-passing

MICROROC is designed to be daisy chained without any external circuitry, thanks to open collector output signals, to limit to a bare minimum the number of output lines on the detector.

Redundant readout lines allow a defect chip to be bypassed.

er: end readout sr: start readout sr2 sr1 chip n−1 er1 sr1 er2 sr2 chip n er1 er2 sr1 sr2 chip n+1 er1 er2

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CSA amplifier

I1 I2 I4 I3 in out

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Temperature study

C] ° Temperature [ 20 30 40 50 60 70 80 90 100 [fC] σ Noise 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 C] ° Temperature [ 20 30 40 50 60 70 80 90 100 [fC] σ Noise 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 All channels Mean Simulation Pedestal [DACu] 0 2 4 6 8 10 12 14

Inflexion Point [DACu]

195 200 205 210 215 220 Pedestal [DACu] 0 2 4 6 8 10 12 14

Inflexion Point [DACu]

195 200 205 210 215 220 C ° 25.5 C ° 47.0 C ° 68.5 C ° 87.0 C ° 105.0 C] ° Temperature [ 30 40 50 60 70 80 90 100 Pedestal [DACu] 200 202 204 206 208 210 212 214 216 C] ° Temperature [ 30 40 50 60 70 80 90 100 Pedestal [DACu] 200 202 204 206 208 210 212 214 216 All channels Mean

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Calibration path

R2 R2 R2 R2 R1 R1 R1 R1 R1 ASU(S) INTERDIF DIF

Strips are 50 Ω, R2=50 Ω and R1=30 Ω. Pulse amplitude is divided by 4.

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Calibration path tests

100 mV test pulse seen with 1 GHz active probe (left: begining of line, right: end of line).

Attenuation of line length has been measured and is corrected during inter-calibration.

Line mismatch is also taken into account.

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I/O Pads

Figure

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References

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