September 18, TWEPP 2012, Oxford, UK

1. A PCI Express Optical Link Based on Low-Cost Transceiver Qualified for Radiation HardnessAndrea Triossi, Diego Barrientos, DamianoBortolato, Roberto Isocrate, Gabriele Rampazzo, SandroVentura and Marco BellatoINFN – Padova and Legnaro September 18, TWEPP 2012, Oxford, UK

2. Outlines Backgrounds • PCI Express • LINCO Project • Early Developments New LINCO Boards • Block diagrams • Jitter test Radiation Tests • Transceiver comparison • PCI Express compatibility

3. Backgrounds PCI Express • 2.5-5-8 Gbps/direction transfer rate • Scalability (up to 32 lanes) • Link Training • Differential signaling • Embedded clock (8b/10b) • De-emphasis • Retransmission of failed packets • Quality of service • PCI address space LINCO Project • Started in 2005 • Investigate a new physical medium for the protocol --> optical fibre • Manufacture copper to optical adapters • Assert their effectiveness in a harsh environment

4. Early development PMC form factor SFP transceivers PCI Ex / PCI bridge PCI to PCI Express optical adapter used in the VME crate of the DT sector collector (CMS) PCI / VME bridge

5. New development PCI Express (x1 lane) optical translator Half height – Half length DMA transfer (128 Byte payload) Max transfer rate 200 MB/s

6. New development x4 optical switch PCI Express Gen2 20 Gbps Downstream port x1 • Two clock domains: • PCI Express spread spectrum • 100 MHz plain clock Downstream port x1 Downstream port x1 Downstream port x1 Upstream port x4 Downstream port x4

7. MOSFET Power Manager POWR1014A I2C MOSFET Differential DC-DC FPGA Spartan3AN DC-DC DC-DC DC-DC SEL0 SEL1 PERST# EEPROM PLX Switch PEX 8609 Mux/Demux PI2PCIE2412 PciEx 4x Finger SFP Transceiver SFP Transceiver PCI Ex x4@5GT/s Mux/Demux PI2PCIE2412 SFP Transceiver REF CLK CLK Fan-out PI6C20400S SFP Transceiver 100 MHz Oscillator CLK Fan-out PI6C20400S

8. Eye diagram 5Gbps Test Setup • 2 PC linked by 30 meters OF and 2 LINCOs (one non-transparent) • 8.5Gbps Finisar transceiver optimized for 4x Fiber Channel Total jitter 0.38 UI @ BER level of 10-12

9. Early radiation test Test Setup • Paul ScherrerInstitut • 63 MeV proton • Maximum total fluence of 5∙1011 p/cm2~66Krad • Avarage flux 0.8 ∙108 ~ 2.8 ∙108 p/cm2/s • VME registers continuously written with random patterns, read back and compared • Total absorbed current monitored No SEU! • Recoverable Micro Latch-up: • Transceiver after 1 Krad • Universe II bridge after 3.5 Krad

10. Transceiver radiation test Test Setup • Paul ScherrerInstitut with 63 MeV proton • Maximum total fluence of 5∙1011 p/cm2~66Krad • Avarage flux 0.8 ∙108 ~ 2.8 ∙108 p/cm2/s

11. Transceiver radiation test

12. Transceiver radiation test Test Setup • Paul ScherrerInstitut with 63 MeV proton • Maximum total fluence of 5∙1011 p/cm2~66Krad • Avarage flux 0.8 ∙108 ~ 2.8 ∙108 p/cm2/s

13. PCI Express compatibility t 1 10-12 Infineon transceiver is not suitable for PCI Express protocol transmission after a radiation dose of 3.2∙1011 p/cm2 Eye opening t

14. Conclusion LINCO Boards • Three flavors • Deployed in several experiments (CMS, AGATA, ICARUS…) Harsh Proton Environment • Commercial transceivers • Intel and Infineon transceivers got through CMS requirement