Gigabit Ethernet PMD Opto-Link Inc. – Presentation 5 Vinh Nguyen February 24, 2005

Gigabit Ethernet: Progress Summary Fixed errors in optical link budget Finished initial schematic design Schematic approved with minor alterations Added details to budget Began looking at board layout Complete initial board layout Board layout design review Order passives and connectors? Completed TasksNext Week’s Tasks

Gantt Chart

Corrected Optical Link Budget

Transmitter Schematic

Receiver Schematic

Estimated Budget

Board Layout and Transmission Lines We looked into the possibility of using short 50 Ω matched transmission lines to improve performance Equations for the capacitance per unit length and inductance per unit length of a microstrip transmission line are fairly easy to find Why bother doing the math when you can use the Internet?

Microstrip Transmission Line Calculator Microstrip transmission line calculator at: – Used 50 Ω target impedance and parameters from the ExpressPCB website A 50 Ω transmission line will have a width of ” ” (2.69mm-2.96mm)

Problems with Line Size Transmission lines will be very wide on the boards Even if we minimize line length, we will still use up a lot of space

Transmission Line Width Comparison

Even Short Transmission Lines Take Up A Lot of Space

Transmission Line Summary Using transmission lines would probably improve performance It would be hard to fit the transmission lines on the MiniBoards Larger boards would result in increased costs

Next Week Make adjustments to schematic Complete initial board layout Board layout design review Research and order passives? Refine budget

References ECE164 Group 2 Presentations. (April 17, 2004). ECE164 Group 2 Website. Retrieved February 24, 2005 from University of Missouri-Rolla Electromagnetic Compatibility Laboratory. (February 23, 2005). Microstrip. Retrieved February 24, 2005 from Various vendor and manufacturer websites