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Senior Design Project: Group IV. Gigabit Ethernet Optical Transceiver Group Members: Jinesh Karia Rakesh Soni James Cummings Elisa Hurwitz Bishan Patel. Finished soldering Transmitter.. Ran into wall of problems Failed to get eye diagrams
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Senior Design Project: Group IV Gigabit Ethernet Optical Transceiver Group Members: Jinesh Karia Rakesh Soni James Cummings Elisa Hurwitz Bishan Patel
Finished soldering Transmitter.. Ran into wall of problems Failed to get eye diagrams Countless hours on debugging (sometimes till 4 in the morning!!!!!) Board surgery done on more than one incident Plans for the last few days In the past week..
Problems Faced • Power connectors - defective part • While changing power connectors, a little more force and the traces came off • Board layout had two main problem • Ibias & Imod currents were feeding the wrong pin of the VCSEL • Pin 11 was left floating instead of Vcc • Ground plane was not cut as needed
Problems continued • Differential input to Maxim chip had different DC and AC components • Voltages on the pin 4 and pin 5 were not up to the specs • Only able to obtain a eye diagram for D28.5 which has significant jitter
Solutions Anode • Surgery was performed to fix the Itotal problem • Replaced the missing traces • Plans for new board Imod Ibias Cathode
Eye Diagram D 21.5 The only one that worked
Problems still being looked at.. • AC component at pin 4 vs pin 5 • Compared to working board huge difference in DC value • 2 volts compared to 5 volts on working board
Finding a solution FAST • All four VCSELs were tried, without success • Changed Maxim 3267 chip twice • Replaced Rmod • Checked Values all around the board • VCSEL was tested to be working on Nickolas’s testing board • Did not make a difference
Possible problem with Imod VCSEL could be damaged More debugging Second board fabrication should be in on Monday Next Step
Work to be done… • Get that Transmitter Working real FAST! • Finish working on the Final Paper.