1. Electronics System Review
The Read-Out system
for the CMS
Drift Tube Chambers.
Electronics System Review
CERN. November 3rd, 2003

2. 1. 2. 3. 4. 5. 6. Index The Read-Out System. Design Requirements.
ESR FOR MUON DT MINICRATE SYSTEM. The Read-Out System.
November 3rd , 2003
Index
The Read-Out System.
Design Requirements.
Read Out Board 1. 2. 3.
HPTDC (High Performance Time to Digital Converter).
ROB architecture and other features
ROB validation tests
ROB production
Conclusions 4. 5. 6.

3. 3
ESR FOR MUON DT MINICRATE SYSTEM. The Read-Out System.
November 3rd , 2003
Read-Out System
The Read-Out system of the CMS DT chambers is based on the READ OUT BOARDS (ROB).
Its aim is:
the time digitalization of the incoming signals from the Front-End electronics of the DT chambers.
the data transmission to the ROS boards, located in the towers in the periphery of the detector, from there to further levels of the DAQ.

4. Location in the CMS Detector4
ESR FOR MUON DT MINICRATE SYSTEM. The Read-Out System.
November 3rd , 2003
Location in the CMS Detector
1 Superlayer Φ
1 Superlayer θ
Honeycomb
MINICRATE
ROB

5. ENVIRONMENTAL RADIATION5
ESR FOR MUON DT MINICRATE SYSTEM. The Read-Out System.
November 3rd , 2003
Design Requirements
RATES
40.08 MHz clock
10-34 cm-2s-1 luminosity, at 25 ns bunch crossing =>
10 Hz/cm-2 charged particles rate.
L1 Accept reduces to 1 Hz/cm2 of muons =>
250 DT-chambers, a total of 172,200 anode channels.
Overlapping triggers due to a drift time of ~400 ns.
Trigger latency of 3.2 s.
100 KHz triggers
~ 1 KHz/DT chamber cell.
neutron fluence 10 years < 1010cm-2
charged particles flux < 10 cm-2s-1
10 year integrated dose ~ 1 Gy
ENVIRONMENTAL RADIATION
Radiation hard devices are not going to be employed, radiation tests have to be performed to every component.
OTHERS
Stray magnetic fields, in the barrel region around 0.08 Teslas.
Limited maintenance for 10 years of operation.

6. Time Digitalization Vdrift ~ cte t  x Overlapping6
ESR FOR MUON DT MINICRATE SYSTEM. The Read-Out System.
November 3rd , 2003
Time Digitalization
Vdrift ~ cte
Tmax drift time~400 ns >> Tbunch crossing 25 ns 1 2 3 4 
Overlapping
t  x 2 3 1 4
Bunch crossing
Drift Time
L1 Accept Latency
Trigger
Time measurement with respect to L1 Accept

7. (High Performance Time to Digital Converter)7
ESR FOR MUON DT MINICRATE SYSTEM. The Read-Out System.
November 3rd , 2003
HPTDC
(High Performance Time to Digital Converter)
Developed by the CERN/EP-MIC group, and produced by IBM in 0.25 m CMOS technology.
 4 registers/channel before L1 buffer.
 4 L1 buffers of 256 words, each shared by 8 channels.
 Triggers stored in 16 words deep FIFO.
 256 words deep readout FIFO.

8. HPTDC OTHER FEATURES LHC clock operation (40.08MHz).
ESR FOR MUON DT MINICRATE SYSTEM. The Read-Out System.
November 3rd , 2003
HPTDC
OTHER FEATURES
LHC clock operation (40.08MHz).
Highly programmable which provides flexibility.
High integration, 32 channels per chip.
Overlapping trigger handling.
Trigger latencies (50 μs) large enough to accommodate our requirements (3.2μs).
Time resolution of ~265 ps RMS in low resolution mode (Required resolution~1ns)
Implemented in a radiation tolerant technology, up to levels of 30 Krad total dose with slight increase in power consumption.
Up to 2MHz hit rates, much more than our needs (noisy channels ~ tens of KHz).
Up to 1 MHz trigger rates, enough for 100 KHz maximum estimated.
Bunch and event identification.
JTAG port for programming and monitoring.
Flexible read-out interface: parallel, serial or byte-wise.
Error flags signalling lost of events, TDC internal errors, etc. and self-bypass on error.

9. ROB Architecture JTAG INTERFACE DIAGRAM 4 HPTDC/ROB (128 channels)9
ESR FOR MUON DT MINICRATE SYSTEM. The Read-Out System.
November 3rd , 2003
ROB Architecture
JTAG INTERFACE DIAGRAM
4 HPTDC/ROB (128 channels)
Compromise between #boards and #unused channels.
 A JTAG interface for configuration and monitoring.
 Clock synchronous token ring passing scheme where one TDC is configured as Master.
 Bypass on error mechanism implemented.
Serializer
parity)
clock
READ-OUT INTERFACE DIAGRAM

10. Other ROB Features READ-OUT POWER SUPPLY 32 bits/HPTDC word10
ESR FOR MUON DT MINICRATE SYSTEM. The Read-Out System.
November 3rd , 2003
Other ROB Features
READ-OUT
32 bits/HPTDC word
Master header and trailer
Error signaling
Timing and positional information (# TDC and # channel).
Byte-wise readout (8 bits data+1 parity+2 byte ID)
DS92LV1021 serializer (12 bits: 10 data + 2 start/stop) at 20 MHz.
POWER SUPPLY
Power consumption: 2.5 V (0.5A) and 3.3V (0.5A) ~ 4 W => ~ 6kW whole system.
Power supply protection circuitry:
In case of 2.5V current consumption over 1.5 A or 3.3V over 1A, power supply is disconnected, with powering on cycles every 700 ms (reduces to 10% power consumption).
Sensor on board for temperature, 2.5V and 3.3V voltage and 2.5 V current monitoring. (Maxim DS2438).

11. ALTERA CPLD CONTROLLER11
ESR FOR MUON DT MINICRATE SYSTEM. The Read-Out System.
November 3rd , 2003
Other ROB Features
ALTERA CPLD CONTROLLER
- An Altera CPLD (EPM7128AE) manages the the Data_Ready/Get_Data transmission protocol slowing down the readout frequency to 20 MHz.
- Manages the channels enabling mechanism for testing chambers during spill interleaves, simulating artificial tracks.
- Controls bytes order from HPTDC words.
Triple redundancy on ALTERA FPGA registers.
Allows detection and reparation of 1 bit upset in a CPLD register due to Single Event Upsets (SEU) from radiation. (Updated every 25 ns). d 1 2 3 q
FF1
FF2
FF3
SEU <= (FF1 xor FF2) or
(FF1 xor FF3) or
(FF2 xor FF3)
Also a SEU counter implemented for radiation tests.

12. 12
ESR FOR MUON DT MINICRATE SYSTEM. The Read-Out System.
November 3rd , 2003
Test Pulses mode
Mode operation for testing chamber channels and electronics during spill interleaves, simulating artificial tracks.
Originated by a TTC command. XX TTC timing and ??
Altera CPLD manages the mechanism of enabling/disabling accordingly the ROB LVDS receiver channels.
Enable TDC 0 ch 0-3
Enable TDC 0 ch 0-7
Enable TDC 0 ch 7-12
TEST MODE
... T1 T2 T3

13. ROB-ROS link Read Out Boards (ROB) CMS DETECTOR DDU13
ESR FOR MUON DT MINICRATE SYSTEM. The Read-Out System.
November 3rd , 2003
ROB-ROS link
DT chamber
Read Out Boards (ROB)
Towers
Read Out Server boards (ROS)
Link bandwidth: 240 Mbps. Throughput: 16Mbps.
Measured BER < 10-15
30m FTP Cat. 6 AC coupled LVDS link
1500
DDU
USC55 Control Room
100 m. Optical link
Link max. Bandwidth: 800Mbps.
Throughtput: 270Mbps. 60
CMS DETECTOR

14. 14
ESR FOR MUON DT MINICRATE SYSTEM. The Read-Out System.
November 3rd , 2003
ROB Connections
128 LVDS signals from DT chambers. Transmitted to Trigger logic, previously converted to TTL level.
ROBUS (RO-MC control bus):
Independent point to point clock connections are used to minimise interference effects.
FTP Cat.6 cable for ROB-ROS link.
- Independent powering up signals (up to 7 ROB´s)
- ROB address lines (4, up to 15 boards)
- JTAG lines
- other control lines (test pulses...)
TRB connections
From DT chambers
3.3V power supply
22.6 cm
9.8 cm
Thermal dissipation areas
ROBUS
(back)
40MHz clock
ROB-ROS link

15. Minicrate (MC) MINICRATE 250 Minicrates 1500 ROB´s: -1440 Rob-128
ESR FOR MUON DT MINICRATE SYSTEM. The Read-Out System.
November 3rd , 2003
Minicrate (MC)
250 Minicrates
1500 ROB´s:
-1440 Rob-128
-60 ROB-32
MB1
MB2
MB3
MB4
Power supply
40A
1.5A
to ROS
MINICRATE
TRB
TRB
TRB SB
Chamber signals
Link
board
RO-
Link
board
ROBUS
ROB
ROB
CCB
ROB
40 MHz CLOCK
RO-link
TTC+Slow control

16. IRRADIATION FACILITY, GIF. (CERN)16
ESR FOR MUON DT MINICRATE SYSTEM. The Read-Out System.
November 3rd , 2003
ROB Validation Tests
TEST BEAMS AT GAMMA
IRRADIATION FACILITY, GIF. (CERN)
Oct. 01: test beam at GIF. Including a 25 ns structured beam ~ 5 Ktrig/s.
MB2 chamber operated under real gas and voltage conditions.
With and without gamma background during acquisition.
May. 03: One full Minicrate operational with a Ros-8 prototype.
Validation with overlapping triggers
No significant errors were found neither in HPTDC nor in the ROB design,
(incorrect wordcount when using local headers).
TDC can stand high hit rates, including noisy channels (~MHz) and this only affects 1 group of 8 channels.

17. ROB Validation Tests IRRADIATION TESTS17
ESR FOR MUON DT MINICRATE SYSTEM. The Read-Out System.
November 3rd , 2003
ROB Validation Tests
IRRADIATION TESTS
Cyclotron Research Centre at the Catholic University of Louvain (UCL), Bélgica.
60 MeV proton irradiation.
Fluence: 5·1010 p.cm-2
SEU: MTBFHPTDC = 3.8 days in the whole detector
MTBFALTERA = 3.4 days in the whole detector
Regulators (MIC BU, MIC BU): ΔV<1%
Rest of ROB IC´s: No effect

18. ROB Validation Tests TEMPERATURE CYCLING LIFETIME TESTS 70ºC 0.2ºC/min18
ESR FOR MUON DT MINICRATE SYSTEM. The Read-Out System.
November 3rd , 2003
ROB Validation Tests
TEMPERATURE CYCLING
70ºC
0.2ºC/min
0ºC
- Regulators: Small variations (< 5mV/30ºC).
- 2.5V current variations of 0.4 mA/ºC.
- Timing measurement variation: 900 ps/70ºC (14 ps/ºC). Max variation ~ 45 ps/ºC.
30% due to LVDS receivers (DS90LV048).
LIFETIME TESTS
- ROB fully operational at 105ºC ambient temperature for 4 months (3100 hours).
- No device has shown any failure.

19. ROB Validation Tests Time resolution Time shift < 200 ps19
ESR FOR MUON DT MINICRATE SYSTEM. The Read-Out System.
November 3rd , 2003
ROB Validation Tests
Time resolution
Neighbour channels crosstalk
Time measurement shift in one ROB channel due to neighbour signals.
Time shift < 200 ps
Low resolution bin size: ns
Measured resolution: 265 ps
Link reliability
RO link to ROS-8 prototype has been tested using a TTC system (TTCvi, TTCex, TTCrx).
Measured jitter on ROB with TTC clock: ~40ps RMS; ~380ps pk-pk
BER < 10-15
No observed influence of TTC commands.

20. 20
ESR FOR MUON DT MINICRATE SYSTEM. The Read-Out System.
November 3rd , 2003
ROB Production
 Several prototypes of ROB´s have been made, we are now confident on its operation.
 PCB´s for ROB-128 and ROB-32 have already been produced.
 An error was found in the engineering run of the HPTDC that had never been shown, presumably due to metallization process.
 Its consequence is a very low yield of the produced HPTDC´s. Exhaustive tests that identify the error have been developed.
 Production run showed 350 “good” HPTDC´s received in September, they will be used for:
- 180 ROB´s of the first assembly batch.
- Produce all ROB-32: 60+spares.
 Whole final production batch of HPTDC´s, now being packaged, will be available in December (6000 u.)
- Remaining ROB-128 will be produced then.

21. ROB Production  Assembly is done at the industry: Assembly21
ESR FOR MUON DT MINICRATE SYSTEM. The Read-Out System.
November 3rd , 2003
ROB Production
 Assembly is done at the industry:
Assembly
On error: repairing
Connectorization tests.
On error: repairing
Functional test.
 A test that checks every functionality of the ROB has been developed at Ciemat to validate assembled ROB´s at the industry.

22. 22
ESR FOR MUON DT MINICRATE SYSTEM. The Read-Out System.
November 3rd , 2003
ROB Production
 Before assembling ROB´s in the Minicrates, they will go through a BURN-IN process:
- We do not want to over-stress the boards, only find infant mortality.
- One week at 50ºC ambient temperature powered and clocked.

23. 23
ESR FOR MUON DT MINICRATE SYSTEM. The Read-Out System.
November 3rd , 2003
Conclusions
The design and operation of the ROB has been thoroughly tested with satisfactorily results. It accomplishes with the imposed requirements of reliability and accuracy.
We are confident in the proper operation of these boards inside the CMS environment within the expected radiation levels, trigger and data rates, etc.
Accordingly, the Read-Out Board is ready for final production and installation on Minicrates.