Gigabit Ethernet PMD

ECE135 Group 2 – Presentation 4

Clifton Kerr February 17, 2005

Gigabit Ethernet:Progress Summary

Finalized Gantt chart Ordered VCSELs and

ROSAs Built and tested practice

board Finalized optical link

budget

Finish initial schematic First Design Review Look ahead at board

layout and software

Completed Tasks Next Week’s Tasks

Gantt Chart

Optical Components

We will be using the AOC HFE4391-541 VCSEL and the AOC HFD3381-108 ROSA.

Both optical components being purchased through the same vendor (AOC).

Less expensive shipping costs and parts will arrive at or near the same time.

If one component gets stopped, both may.

AOC HFE4391-541 VCSEL

2.5Gbps, 850nm, SC VCSEL 2.5Gbps VCSEL so better performance Cost: $14.50 for less than 1000

– $7.25 for 1000 or more

In stock and LC connectorized.

AOC HFE4391-541 VCSEL (cont.)

Four corners analysis for AOC HFE4391-541

AOC HFD3381-108 ROSA

2.5Gbps, 850nm, SC-ROSA Cost: $10.00 for less than 1000

– $5.00 for 1000 or more

In stock and LC connectorized This part, like the AOC VCSEL, provided the

best combination of performance, price, and availability

AOC HFD3381-108 ROSA (cont.)

Four corners analysis for AOC HFD3381-108 ROSA

Optical Link Budget

Building the Test Board

Andy solders on a connector. Clif learns the hard way how small the passives really are.

Building the Test Board (cont.)

Vinh works on the top of the board The finished board, with everything connected.

Testing the Test Board

First test was a disaster. Nothing worked. Setup was verified, but time constraints and

illness made us abort further troubleshooting.

Testing the Test Board (cont.)

Second test attempt produced observable results… for a while.

Same setup as for first test.

PRBS7, 0dB source attenuation

Testing the Test Board (cont.)

PRBS7, 30dB attenuation PRBS7, 40dB attenuation

Testing the Test Board (cont.)

Eyes are shown in the order in which they were taken.

With attenuation, it appears that the signal becomes increasingly distorted.

After shots were taken, the signal completely disappeared. It would return momentarily before dropping back to ground.

BER unknown (unable to find signal) because of further signal degradation.

Testing the Test Board (cont.)

Board was hooked up again cold the next day, and eye returned to normal.

Apparently due to bad solder joint, as failure rate increases dramatically with operation time and consequently heat.

To Do: Test cooled board for BER before it slips into failure state. As this is a practice board, we will only address it’s failures if we have time.

Preliminary Budgeting (estimation)

AOC VCSEL: $14.50 (4) AOC ROSA: $10.00 (4) Two board fabs: $110.00 Maxim driver and limiting amp, Digikey

passives, and Murata inductors, plus allowances for shipping costs: $80.00

Total projected budget: – Approximately $290.00

Next Week

Finish initial schematic and submit for design review

Look ahead at board layout and software Start board layout

References

IEEE Computer Society (2003). IEEE 802.3 Standard. New York: The Institute of Electrical and Electronics Engineers, Inc. Retrieved Thursday, January 20, 2005, from ECE 164.02 website: http://www.ee.duke.edu/~mbrooke/EE164.02/Spring_2004/group_2/index_files/8023.pdf

ECE164 Group 1 Presentations. (April 26, 2004). ECE164 Group 1 Website. Retrieved January 20, 2005 from http://www.ee.duke.edu/~mbrooke/EE164.02/Spring_2004/group_1/downloads.html

ECE164 Group 2 Presentations. (April 17, 2004). ECE164 Group 2 Website. Retrieved January 20, 2005 from http://www.ee.duke.edu/~mbrooke/EE164.02/Spring_2004/group_2/presentations.html

AOC datasheets for the HFE 4391-541 VCSEL and HFD 3381-108 ROSA