LECC 2005, HeidelbergA. Vollhardt, EPF Lausanne/Switzerland1 Production of the LHCb Silicon Tracker...
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Transcript of LECC 2005, HeidelbergA. Vollhardt, EPF Lausanne/Switzerland1 Production of the LHCb Silicon Tracker...
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 1
Production of the LHCb Silicon Tracker Readout Electronics
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 2
Outline
Overview of the Readout Electronics
1st preproduction of Digitizer Board
Evaluation of performance Integration with LHCb hardware 2nd preproduction Conclusion
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 3
LHCb Silicon Tracker principle
Two distinct tracking systems based on silicon strip detectors, read out via the BEETLE chip
TT: full acceptance angle covered upstream of magnet
IT: only area of highest track densities around beampipe
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 4
Beetle readout chip
128 channel charge integrator polyimide readout hybrid carries 3
(IT) or 4 (TT) Beetle chips for sensors of 384 (IT) or 512 (TT) strips
See also: Talk of F. Lehner:
Hybrid Design, Procurement and Testing for the LHCb Silicon Tracker
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 5
ST Readout electronics
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 6
Service Box Overview
Digitizer Board
backplane
low-voltage power
sensor + readouthybrids
Digitizer Board
up to 16 hybrids/boards
Control Card
TTC ECS
5m copper cable Optical fibres
for physics data
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 7
Digitizer Board characteristics
6 layer PCB, halogen-free, 1.6 mm thickness, symmetric stack
single side mounting, no buried/blind vias smallest feature size 6 mil, smallest package 0603 5 BGA devices:
1x CS49 (0.8 mm pitch), 3-4x BGA144(1.0 mm pitch) no JTAG chain , no boundary scan differential traces have controlled impedance/length standard commercial connectors NO tuning points layout optimized for low-cost, high-yield, easy testing2 versions:
Trigger Tracker (4-chip readout), Inner Tracker (3-chip readout)
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 8
1. Preproduction run 17 boards produced and electrically tested in late 2004
(TT version) after assembly, all BGAs X-rayed: all solder joints ok! 2 bugfixes:
wrong reference voltage for line receiverAuto-Sync FPGA: shift register one cycle (25ns) too short
all boards except one immediately working:board #10 had ripped via under BGA (fixed)
changes for IT version preproduction (and final production): changed VCSEL biasing added QPLL RC-network for improved jitter stability
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 9
Digitizer Board
Power <5 W Only positive voltages: 2.5 V, 5.0 V
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 10
Beetle signal at ADC
Flat top 15 nsec wide (of 25 nsec max.)
measured with 5m twisted pair cable
plenty of ‘space’ to set ADC sampling point
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 11
Linearity
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 12
Sampling synchronicity I
supply all 16 inputs with ‘synchronous’ testpulse:testpulse generator sourcing 16 LVDS drivers
move sampling time by using TTCrx clock phase shifters (just like in experiment..)
transmit data via GOL+ optical fibres to DACs and scope record pulseheight of sampled edge vs. programmed
delay
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 13
Sampling synchronicity II
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 14
GOL VCSEL connection
VCSEL forward voltage with 2.5V anode voltage results in too low GOL current driver voltage level
only 2.5V and 5V available
reduced to 3.3V by low-impedance divider
blocked at VCSEL with 100nF||100pF
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 15
Eye diagram after 100m
Thanks to Paolo Ciambrone/LHCb Muon
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 16
Auto-sync Beetle DataValid
signal (almost) in parallel to analogue data to frame a triggered event
done via shift register in Actel antifuse FPGA (small version of rad-hard AX54SX32) incl. TMR+ majority voting
Results in at least one IDLE frame per event
Beetle analogue output
Beetle DataValid
Beetle data after digitization
DataValid after 200 ns delay
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 17
Radiation qualification
Expected radiation levels for Service Box location for 10 years:TID 15 krad, NIEL 2E12 n/cm2
all commercial devices individually radiation qualified (TID, NIEL and SEE) with proton and neutron irradiation according to LHCb radiation policy
System test: TT Digitizer Board + backplane re-tested in June 2005 with 60 MeV protons to 60 krad (PSI, Switzerland): analogue test pattern injected verification of function and performance no variations in module operation observed
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 18
Full Readout test
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 19
Full Readout test
LHCb-style readout (except LHCb Readout Supervisor + CPU farm)
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 20
Control Card
Under development by Universidade de Santiago de Compostela Provides TTC signals and slow control interface to each
Service Box and its associated frontend electronics First prototype functional (still being tested)
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 21
Breaking News: IT version
10 Digitizer Boards (IT version preproduction) were delivered last Wednesday
initial testing confirm out-of-the-box functionality
important step: re-validate eye diagram with new VCSEL bias!
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 22
Next steps
detailed testing of IT prototypes: last design verification launch production order after:
production+assembly time for all boards: ca. 8-10 weeks
all parts available except for VCSELs (LHCb common order placed, expected in November)
‘bird-food’ supplied by company, special components by us
start setting up test bench during production:basic functionality test (go-nogo)burn-in test (catch infant mortality)
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 23
Conclusion + Outlook
The preseries production for both versions of the ST Digitizer Board has been completed.
Bugfixes and lessons learned in the TT version were successfully included in the IT version.
Required functionality was verified and system compatibility with common LHCb hardware has been shown.
Preseries hardware is used to form teststands for the TT sensor module production (Zuerich) and the IT sensor production (CERN)
Final qualification pending, design will be released for full production in Q4/05.
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 24
SPARE SLIDES
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 25
Digitizer Board input stage
Bandwidth: 1.6 kHz (AC-Coupling) to 170 MHz (AD8129) Amplifier output range matches ADC input range
3x 1 k
22
39
39
2.5 V
2x 100 nF 8 bits+
-
gain: 11
differential signal from Beetle
AD8129 TSA0801
gain: 0.22impedance: 100 Ohm
100 nF
10 kVcm
Vref (ca. 1 V)
out
out
Output to GOL serializer
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 26
Clock tree
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 27
TFC distribution
Impedance controlled traces for LVDS signals
TTL traces only used for short (~ 2 cm) for fanning out
equal trace lengths to minimize ch-ch skew
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 28
Service Box: frame
Fully loaded weight: ca. 10 kg
Power disipation: ca. 150 W (70 W into mixed water cooled heatsink)
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 29
Service Box cooling
all linear regulators located close to each other
use common copper heatsink (mixed water) to cool all at once
isolate ground slug of regulator package (local ground!)
used for testing: CPU water cooling system: no active cooler, but fan-blown heat-exchanger
Test at full load results in 35 degC case temperature for 25 degC water (=ambient temperature)
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 30
IT mounting
Service Boxes outside acceptance
Mounted on common IT station frame
‘5m copper cables’ no not move
cables from Service Box away from detector move (cable chains)
LECC 2005, Heidelberg A. Vollhardt, EPF Lausanne/Switzerland 31
TT mounting
Service Boxes mounted outside acceptance to magnet
‘5m copper cable’ guided in cable chains to station halves
cables away from Service Box fixed in cable trays