Gigabit Ethernet PMDOpto-Link, Inc. – Status Report 9

Vinh Nguyen

April 14, 2005

Gigabit Ethernet:Progress Summary

Completed Tasks Finished

troubleshooting Updated Bill of

Materials Updated budget to

reflect latest purchases

Next Week’s Tasks Complete second board

layout Design review for next

fabrication Place order for board

fabrication Assemble second board

Gantt Chart

Current BudgetPart Description: Manufacturer: Vendor: Vendor Part Number: Unit Cost: Quantity: Total Part Cost:

CAP 10000PF 50V CERAMIC X7R 0603 (back ordered) BC Components Digi-Key BC1252CT-ND $ 0.0290 100 $ 2.90

RES 30.0 OHM 1/10W 1% 0603 SMD Rohm Digi-Key RHM30.0HCT-ND $ 0.0760 10 $ 0.76 RES 100 OHM 1/10W 1% 0603 SMD Rohm Digi-Key RHM100HCT-ND $ 0.0760 10 $ 0.76 RES 115 OHM 1/10W 1% 0603 SMD Rohm Digi-Key RHM115HCT-ND $ 0.0760 10 $ 0.76 RES 3.00K OHM 1/10W 1% 0603 SMD Rohm Digi-Key RHM3.00KHCT-ND $ 0.0760 10 $ 0.76 POT 1.0K OHM 3/8" SQ CERM SL MT Bourns Inc Digi-Key 3296W-102-ND $ 2.5000 5 $ 12.50 POT 10K OHM 3/8" SQ CERM SL MT Bourns Inc Digi-Key 3296W-103-ND $ 2.5000 5 $ 12.50

FERRITE CHIP 1000 OHM 100MA 0603Murata Electronics North America

Digi-Key 490-1034-1-ND $ 0.1200 50 $ 6.00

PCB Fabrication Run Express PCB Express PCB $ 59.0000 1 $ 59.00

AOC 2.5 Gbps VCSEL Advanced Optical Components Advanced Optical Components HFE419x-541 $ 14.5000 4 $ 58.00

AOC 1.25/2.5 Gbps ROSA Advanced Optical Components Advanced Optical Components HFD3180-103 $ 10.0000 4 $ 40.00

CONN PWR JACK 2.1MM SMD CUI Inc. Digi-Key CP-002APJ-ND $ 0.7300 6 $ 4.38 Right-Angle SMA Jack Amphenol Jameco 188525 $ 4.2000 10 $ 42.00

CAP 10000PF 50V CERAMIC X7R 0603 BC Components Digi-Key BC1252CT-ND $ 0.0169 100 $ 1.69 RES 100 OHM 1/10W 1% 0603 SMD Rohm Digi-Key RHM100HCT-ND $ 0.0760 20 $ 1.52 RES 200 OHM 1/10W 1% 0603 SMD Rohm Digi-Key RHM200HCT-ND $ 0.0760 10 $ 0.76 RES 2.00K OHM 1/10W 1% 0603 SMD Rohm Digi-Key RHM2.00KHCT-ND $ 0.0760 10 $ 0.76 RES 24.9 OHM 1/10W 1% 0603 SMD Rohm Digi-Key RHM24.9HCT-ND $ 0.0760 10 $ 0.76 RES 34.8 OHM 1/10W 1% 0603 SMD Rohm Digi-Key RHM34.8HCT-ND $ 0.0760 10 $ 0.76 Shipping and Handling $ 22.28

Total: $ 268.85

Projected BudgetPart Description: Manufacturer: Vendor: Vendor Part Number: Unit Cost: Quantity: Total Part Cost:

CAP 10000PF 50V CERAMIC X7R 0603 (back ordered)

BC Components Digi-Key BC1252CT-ND $ 0.029 100 $ 2.90

RES 30.0 OHM 1/10W 1% 0603 SMD Rohm Digi-Key RHM30.0HCT-ND $ 0.076 10 $ 0.76

RES 100 OHM 1/10W 1% 0603 SMD Rohm Digi-Key RHM100HCT-ND $ 0.076 10 $ 0.76

RES 115 OHM 1/10W 1% 0603 SMD Rohm Digi-Key RHM115HCT-ND $ 0.076 10 $ 0.76

RES 3.00K OHM 1/10W 1% 0603 SMD Rohm Digi-Key RHM3.00KHCT-ND $ 0.076 10 $ 0.76

POT 1.0K OHM 3/8" SQ CERM SL MT Bourns Inc Digi-Key 3296W-102-ND $ 2.500 5 $ 12.50

POT 10K OHM 3/8" SQ CERM SL MT Bourns Inc Digi-Key 3296W-103-ND $ 2.500 5 $ 12.50

FERRITE CHIP 1000 OHM 100MA 0603Murata

Electronics North America

Digi-Key 490-1034-1-ND $ 0.120 50 $ 6.00

PCB Fabrication Run Express PCB Express PCB $ 59.000 2 $ 118.00

AOC 2.5 Gbps VCSELAdvanced Optical

ComponentsAdvanced Optical

ComponentsHFE419x-541 $ 14.500 4 $ 58.00

AOC 1.25/2.5 Gbps ROSAAdvanced Optical

ComponentsAdvanced Optical

ComponentsHFD3180-103 $ 10.000 4 $ 40.00

CONN PWR JACK 2.1MM SMD CUI Inc. Digi-Key CP-002APJ-ND $ 0.730 6 $ 4.38

Right-Angle SMA Jack Amphenol Jameco 188525 $ 4.200 10 $ 42.00

CAP 10000PF 50V CERAMIC X7R 0603

BC Components Digi-Key BC1252CT-ND $ 0.017 100 $ 1.69

RES 100 OHM 1/10W 1% 0603 SMD Rohm Digi-Key RHM100HCT-ND $ 0.076 20 $ 1.52

RES 200 OHM 1/10W 1% 0603 SMD Rohm Digi-Key RHM200HCT-ND $ 0.076 10 $ 0.76

RES 2.00K OHM 1/10W 1% 0603 SMD Rohm Digi-Key RHM2.00KHCT-ND $ 0.076 10 $ 0.76

RES 24.9 OHM 1/10W 1% 0603 SMD Rohm Digi-Key RHM24.9HCT-ND $ 0.076 10 $ 0.76

RES 34.8 OHM 1/10W 1% 0603 SMD Rohm Digi-Key RHM34.8HCT-ND $ 0.076 10 $ 0.76

Shipping and Handling $ 22.28

Total: $ 327.85

Estimated Bill of MaterialsPart Description: Manufacturer: Mfg. Part Number: Vendor:

Vendor Part Number:

Unit Cost:Quantity/Board:

Total Part Cost:

CAP 10000PF 50V CERAMIC X7R 0603

BC Components VJ0603Y103KXACW1BC Digi-Key BC1252TR-ND 0.00346 18 0.06228

RES 30.0 OHM 1/10W 1% 0603 SMD Rohm MCR03EZPFX30R0 Digi-Key

RHM30.0HTR-ND 0.00203 1 0.00203

RES 100 OHM 1/10W 1% 0603 SMD Rohm MCR03EZPFX1000 Digi-Key RHM100HTR-ND 0.00203 3 0.00609

RES 115 OHM 1/10W 1% 0603 SMD Rohm MCR03EZPFX1150 Digi-Key RHM115HTR-ND 0.00203 1 0.00203

RES 3.00K OHM 1/10W 1% 0603 SMD Rohm MCR03EZPFX3001 Digi-Key

RHM3.00KHTR-ND 0.00203 1 0.00203

POT 1.0K OHM 3/8" SQ CERM SL MT Bourns Inc 3296W-1-102 Digi-Key 3296W-102-ND 1.092 1 1.092

POT 10K OHM 3/8" SQ CERM SL MT Bourns Inc 3296W-1-103 Digi-Key 3296W-103-ND 1.092 1 1.092

MAX3286 Laser Driver Maxim IC MAX3286+CTI Maxim IC MAX3286+CTI 4.07 1 4.07

MAX3264 Limiting Amplifier axim IC MAX3264CUE+ Maxim IC MAX3264CUE+ 4.00 1 4.00

PCB Fabrication Run Express PCB Production Service Express PCB 1.35438 1 1.35438

AOC 2.5 Gbps VCSEL AOC HFE419x-541 AOC HFE419x-541 7.25 1 7.25

AOC 1.25/2.5 Gbps ROSA AOC HFD3180-103 AOC HFD3180-103 5 1 5

Total Per Board: $23.93

Transmitter Testing Last week’s transmitter

problems persisted Testing resulted in closed

“eyes” for both the AOC and the Emcore board designs

The VCSEL is lasing but no signal is getting though to the receiver

Probing the board resulted in a blown inductor

Transmitter PRBS7 Signal with no attenuation

Troubleshooting Hypothesis: Limiting resistor values may be

incorrect Would prevent the VCSEL from receiving

enough current to bias it above threshold Adjusting the potentiometers would have little

effect on the output signal beyond a certain level

Testing the Hypothesis Set bias potentiometer to high resistance Shorted the limiting resistor Reduced the potentiometer resistance Resulted in closed eye Continued reduction of potentiometer

resistance resulted in a blown Emcore VCSEL Probing the AOC board design resulted in

another blown VCSEL

Repairs Replaced all damaged components on the

Emcore design Testing the repaired board resulted in closed

eyes again Tried to systematically tune potentiometers

Careful tuning did not result in open eyes Carefully probed inputs and outputs

Test Signals

D21.5 input signal obtained using the probe Output signal for D21.5 input obtained using the optical test equipment

Test Signals Cont. Tried using PRBS7 test signal as input

PRBS7 input obtained using the probe plotted beside the clock signal

The Magic Probe Probing between the laser driver and the

VCSEL resulted in the “Magic Probe Effect” The optical output signal formed excellent

eye diagrams when the probe leads were placed between the laser driver and the VCSEL

Magic Probe Results

Eye diagram for optical output for PRBS7 input with probe

Possible Explanations The use of smaller potentiometers may have

resulted in the overdriving of the laser driver chip

Board layout issues Unbalanced circuit Weird layout effects

Testing Hypothesis Replaced the bias potentiometer with a larger

50 kΩ potentiometer from the practice board Unable to obtain an open eye diagram by

tuning the potentiometer Can still obtain good eye diagrams using the

“Magic Probe” Effectively rules out overdriving hypothesis Only leaves potential layout issues

Next Week Complete second board layout

Second board layout will use passive components to try to replicate the effect of the probe on the board

Design review for next board fabrication? Place order for board fabrication Start Final Report Assemble second board Get board blessed in chapel

Board Layout Review