Jitter and BER measurements on the

CuOF prototypeG. Dellacasa, G. Mazza – INFN TorinoCMS Muom Barrel WorkshopCERN, February 25th, 2011

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Outline

CuOF boards short description Test bench description Jitter measurements results BER results Design of the Versatile Link prototype board:

GBT13 Laser Driver (GBLD) jitter measurements results

Conclusions

CMS Muon Barrel Workshop 25th February 2011

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CuOF prototype

Proposal: to move ROS and TSC from UXC55 to USC55

Needs to fabricate the optical transmitters (UXC55) and the optical receivers (USC55)

Cu to Optical Fiber (CuOF) prototype board has been developed at CIEMAT to evaluate the best candidates for the line equalizer and laser driver to use. TX hosts: 2 line equalizer: LMH0024 and MAX3800 3 laser driver: MAX3643, MAX3646 and SY88216

CuOF RX hosts Finisar FTLF8519F2 optical receiver The 6 possible combinations in the TX board have

been tested

CMS Muon Barrel Workshop 25th February 2011

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Test bench

CuOF TX and RX

Agilent 16702B: 200MHz LSA / 300 MHz

Pattern Gen. Tektronix DPO 70604: 6GHz; 25 GS/s

Stanford Research SRS-CG635: 2.05 GHz clock and

PRBS data generator

Agilent N5980A: 3.125 Gb/s BERT

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Instrumentation details

Agilent LSA /Pattern Generator: used for preliminary tests PRBS data generation and data out checks Not good enough for real tests (only 300 Mb/s generator and 200

MHz LSA). Also its jitter is not adequate: 105 ps rms random jitter @ 240 Mb/s

Tektronix 6 GHz oscilloscope: used for jitter analysis SRS-CG635: used as PRBS data generator (fixed pattern 27-1, at

any rate). Its jitter performances are very good: 1.95 ps rms @ 240Mb/s and 1.81 ps rms @ 480 Mb/s (random jitter)

Agilent N5980A: BER tester. Only most common serial communication standards are supported (so not our whished rates)

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CuOF TX and RX details

In order to connect the two boards to the instruments, home made adapters have been inserted (2-pin to SMA connectors). This of course can degrade quality of signals and it has to take into account in the final results

All the measurements (jitter and BER) have been taken at the end of the transmission channel (TX + fiber 40 cm + RX)

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Jitter measurements: 240 Mb/s

PRBS: 27-1Jitter contributions summary

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LMH0024 + MAX3643 LMH0024 + SY88216 MAX3800 + MAX3646LMH0024 + MAX3646 MAX3800 + SY88216MAX3800 + MAX3643

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Period jitter rms [ps]

Deterministic jitter (pk-pk) [ps]

Data dependent (ISI) [ps]

Random jitter rms [ps]

Eye opening @BER 10 E-12 [UI] %

Maxim and Micrel datasheet:

MAX3643 -> up to 2.5 Gb/s

MAX3646 -> up to 622 Mb/s

SY88216 -> up to 2.5 Gb/s

CMS Muon Barrel Workshop 25th February 2011

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Jitter measurements: 480 Mb/s

PRBS: 27-1Jitter contributions summary

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LMH0024 + MAX3643 LMH0024 + SY88216 MAX3800 + MAX3646LMH0024 + MAX3646 MAX3800 + SY88216MAX3800 + MAX3643

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Period jitter rms [ps]

Deterministic jitter (pk-pk) [ps]

Data dependent (ISI) [ps]

Random jitter rms [ps]

Eye opening @BER 10 E-12 [UI] %

Maxim and Micrel datasheet:

MAX3643 -> up to 2.5 Gb/s

MAX3646 -> up to 622 Mb/s

SY88216 -> up to 2.5 Gb/s

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LMH0024 + MAX3643 480 Mb/s

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LMH0024 + SY88216 480 Mb/s

Asymmetry in rising / falling edges (falling edge is faster) Jitter is visible

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MAX3800 + MAX3646 480 Mb/s

Jitter is visible

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LMH0024 + MAX3646 480 Mb/s

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MAX3800 + SY88216 480 Mb/s

Asymmetry in rising / falling edges (falling edge is faster) Jitter is visible

CMS Muon Barrel Workshop 25th February 2011

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MAX3800 + MAX3643 480 Mb/s

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BER

The Agilent BER tester supports only the most common serial communication standards

The BER has been measured using the OC-12 standard. Its rate is 622.08 Mb/s (more than our needs!)

Data sequence: PRBS 27-1 Each channel tested for one hour For all the 6 combinations in the TX board (equalizer + laser

driver) no errors where observed (also with LMH0024 which has declared data rates 125 Mb/s to 540 Mb/s)

BER < 10-11

The Agilent BER tester has an optimum data recovery circuit. To see if these results will be confirmed in the final system with ROS and TSC receivers

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Versatile Link

GBLD

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Jitter measurements @ 5Gb/s

Ipre=0 TJ= 32.90 psRJ=0.62 psDDJ=24.78 psDCD =3.08 psISI=22.25 ps

Ipre=3.6 mA TJ= 22.39 psRJ=0.61 psDDJ=14.56 psDCD =2.31 psISI=11.61 ps

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Conclusions

At the required data rates (240 Mb/s and 480 Mb/s) all the combinatorial of the components present on the CuOF prototype board behaved successfully

Jitter behaviour seems to be dominated by the laser drivers. Best performance is given by the MAX3643 (Maxim) and worst performance by the SY88216 (Micrel). The latter is to be understood because has an unexpected jitter’s value for its nominal characteristics (2.5 Gb/s). A second CuOF board would be useful for comparison

BER seems to be very good (<10-11) at these data rates Next steps:

to study the CuOF board within the real system in order to evaluate the impact of other components (data from Minicrates, cables and fibers length, TSC and ROS receivers etc.)

design and test of the Versatile Link prototype board with both GBLD and commercial laser drivers

define (hopefully before the end of 2011) the required interfaces and study of the system integration (voltage regulators? DCS? Programmable options? Mechanical integration? Etc.. etc..)