GIGABIT ETHERNET DESIGN ECE 164 02 Spring 2004

GIGABIT ETHERNET DESIGN ECE 164. 02 - Spring 2004 Group 1 Presentation 5 – Yashar Pirzadeh

Week 6 Progress Summary l l l Updated Schematic Design with Recommended Updates Made Initial Board Layout and First Revisions Show Practice Board Transmitter Tests Again Review Optical Link Budget Ordering Parts (including Passives) Updated Gantt Chart

Gantt Chart

Practice Board Transmitter Receiver

Transmitter Assembly (cont. ) Back of Board (scraping to eliminate bad grounds)

Transmitter Testing 10 d. B Attenuation – BER = 0 E-9 for 30 seconds

Transmitter Testing 10 d. B Attenuation – BER = 10 E-9 for 30 seconds

Transmitter Testing Failure = 50 d. B, BER= 10 E-7 for 30 seconds

Transmitter Testing Bit Error Rate Readings @ 10 d. B Attenuation (10 E-9)

Optical Link Budget l Decided on Hamamatsu PD – – l l $18 -20 for 1 -99 quantity $6. 50 for 10, 000+ quantity No luck with VCSEL Passives ordered within next forty-eight hours via credit card to be reimbursed – Budget for these calculated and presented next week

Optical Link Budget Considerations l VCSEL – – – l Lowest Imin is above the lowest Ith Provides enough current to drive VCSEL Those who cannot drive current eliminated Hamamatsu PD – – Picture shows 0. 85 p. F capacitor, 0. 010 m. A current Our current is much higher but capacitance worse Rough extrapolation: it should work Those who didn’t pass this test eliminated

Review of Schematic Changes l Minimal: Removed RC Circuit from Receiver l Important Considerations: – Tight loops, filters, and power supply location

Transmitter Schematic Design

Original Receiver Schematic Design

Revised Receiver Schematic Design

Review of Board Layout Changes l Overall – – l More overall symmetry 45 degree angles for wires, no reflection of high frequency signals Transmitter – – – VCSEL straight angle into 3287 through capacitor Problem: Capacitor about 2 mm, only 4 mm space before transmission line issues Missing portions from Tx schematic included

Board Layout Revisions (contd. ) l Receiver: – – Curve the shield around receiver, ground it Keep power away from high frequency signals

Original Board Layout

Revised Board Layout

Next Week’s Agenda (and beyond) l l l Spring Break Hopefully board is available Begin building board with available parts Nag vendors whose parts are missing Formal Budget Update Gantt Chart

THE END l Group Members – Russell Cook – Yashar Pirzadeh – James Dezelle