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Project GabE ECE 135 – Spring 2005 Final Presentation

Project GabE ECE 135 – Spring 2005 Final Presentation. Omar Al-Jadda Patrick Crosby Adam Durity Rahmin Sarabi. Progress Report. Built final board design Tested and verified Tx Tested and verified Rx Loopback Testing. Gantt Chart. Project Overview.

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Project GabE ECE 135 – Spring 2005 Final Presentation

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  1. Project GabEECE 135 – Spring 2005Final Presentation Omar Al-Jadda Patrick Crosby Adam Durity Rahmin Sarabi

  2. Progress Report • Built final board design • Tested and verified Tx • Tested and verified Rx • Loopback Testing

  3. Gantt Chart

  4. Project Overview • Research 802.3 Gigabit Ethernet standard • Learn to use the test equipment • Analyze and select optical components to be used • Design and build both an aggressive and a conservative prototype of a 1.25Gbps Optical Gigabit Ethernet PMD

  5. Evaluation Board • Tested MAX3287, MAX3266, MAX3264 evaluation boards • Varied attenuation from 0dB down to 70dB • BER = 10^-9 @ 10dB

  6. Test Board • Built test board using parts provided • Tested board at 10dB and 30dB • BER = 10^-9 @ 10dB

  7. VCSEL • Criteria for selecting VCSEL: • High slope efficiency • Low threshold current • At least 1.25Gbps • We chose the Advanced Optical Components HFE4191-541

  8. ROSA • Criteria for selecting ROSA: • High responsivity • High transimpedance • We selected the Advanced Optical Components HFD3180-102

  9. GabE Final Schematic - Tx

  10. GabE Final Schematic - Rx

  11. Conservative Board Designs GabE 1.0 GabE 2.0

  12. Aggressive Board Designs GabE 1.0 GabE 2.0

  13. Aggressive vs. Conservative • Conservative is designed with one key objective in mind: functionality • Aggressive design achieves LC connector spacing • Aggressive design violates many design rules: asymmetric, long traces

  14. GabE 2.0 Conservative Aggressive

  15. “Plug ‘n’ Play” Required no additional fiddling Basis for Tx, Rx, and loop-back tests Conservative Board

  16. TOSA-ROSA Distance meets LC Specification After build; did not work right away Blew an inductor; smoke etc… Short to ground Separated Tx and Rx Tried to isolate short Aggressive Board

  17. Discovered that Tx chip was cause of short! Also destroyed a pin on the LA; used wire jumper Soldered on a new Tx Chip No short to ground Still does not work Aggressive Board

  18. Board Building Tips from Ωr • Solder chips on first, carefully, and check the notch! • Solder on smaller passives then larger components, TOSA/ROSA last • Fine tipped soldering iron at 650°F; high gauge solder • Use needle nose pliers to hold in place the SMT component; touch the soldering iron to the solder to form a bead, solder joint

  19. Tx Testing - Conservative • Attempted to tune potentiometers, but found that they have little to no effect • Tested Circuit for 10, 20, 30, 50 and 70dB of attenuation

  20. Tx Testing - Conservative 10dB High Rbias, High Rmod 10dB High Rbias, Low Rmod 10dB Low Rbias, Low Rmod 10dB Low Rbias, High Rmod

  21. Tx Testing - Conservative 10dB Rbias = 500Ω, Rmod = 12.5kΩ

  22. Tx Testing - Conservative 30dB Rbias = 500Ω, Rmod = 12.5kΩ

  23. Tx Testing - Conservative 70dB Rbias = 500Ω, Rmod = 12.5kΩ

  24. Tx Testing - Aggressive 1.0 0dB/810ohm

  25. Tx Testing - Aggressive 2.0

  26. Aggressive Board

  27. Possible Problems • Broken pin on Maxim Chip • Burned Inductor • Burned out traces • Soldering problems

  28. Rx Testing - Conservative 0dB 4dB

  29. Rx Testing - Conservative 7dB 12dB

  30. Loopback - Conservative • Based on Tx Testing, set Rbias and Rmod to 500Ω 12.5k Ω respectively • Tested with 10 and 70dB electrical attenuation and 0 and 9dB optical attenuation

  31. Loopback - Conservative 10dB Electrical 0dB Optical Rbias = 500Ω, Rmod = 12.5kΩ

  32. Loopback – Conservative 70dB Electrical 9dB Optical Rbias = 500Ω, Rmod = 12.5kΩ

  33. Bit Error Rate Tests • Loopback • Electrical: 70dB; Optical: 9dB;BER=10^-10 • Electrical: 10dB; Optical: 9dB;BER=10^-10 • Receiver • Optical: 12dB;BER=10^-10 • Transmitter • Electrical: 70dB;BER=10^-10

  34. Financial Budget

  35. Bill of Materials

  36. Upcoming Week • Complete Final Report

  37. Conclusion • ROSA – the solution to the crosstalk problem • ROSA – allows prices to be competative with electrical GbE • Learned skills in project management: Gantt charts, working with vendors, how to work as a team, allocation of time and resources

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