ECE 135 Final Presentation The Three … aka Pat Cleary with Kevin Parker & Bryan Chavez April 21 st, 2005 April 21 st, 2005

ECE 135 Final Presentation The VCSEL Kings … aka Pat Cleary with Kevin Parker & Bryan Chavez April 21 st, 2005 April 21 st, 2005

ECE 135 Final Presentation RIO! … aka Pat Cleary with Kevin Parker & Bryan Chavez April 21 st, 2005 April 21 st, 2005

ECE 135 Final Presentation BtrLaytDanNvr Pat Cleary with Kevin Parker & Bryan Chavez April 21 st, 2005 April 21 st, 2005

Introduction The Goal: An IEEE Standard Gigabit Ethernet Link The Components: Group and time management plan, background research, part selection, optical link budget, circuit design and layout, construction, and troubleshooting.

Initial GANTT Chart

Group Management Task Task Leader Primary Support Organizational Management PatKevin Optical Link Design KevinBryan Board Layout BryanPat Board Construction BryanPat TestingKevinBryan Report Prep PatKevin

Background Research: Overview

Background Research: Tx

Background Research: Rx

Background Research for Four-Corners Analysis Eye safe limit → P max = 1 mW From the standard → extinction ratio = 9dB Thus we see that P min = P max *10^(-9/10) P min = mW

VCSEL Four Corner Analysis HFE439x-521 ManufacturerPartI_th (mA) η (mW/mA) I_tot(MAX) (mA) I_tot(MIN) (mA)I_bias (mA)I_mod (mA) Advanced Optical Components (2.5G) SCHFE439x Advanced Optical Components (2.5G) SCHFE439x Advanced Optical Components (2.5G) SCHFE439x Advanced Optical Components (2.5G) SCHFE439x

ROSA Selection HFD ROSA Part # Min (V/W)Typical (V/W)Max (V/W) Advanced Optical Components (up to 2.5) (LC) HFD

Optical Link Budget Advanced Optical Components HFE419x-541 with HFD ROSA Ith (mA) 1.8 DC Bias of laser (mA) Slope Efficiency (mW/mA) Modulation Current of Tx (mA) Range of Power Output (mW) Range of Power at Rx (mW) – 7.5 dB Loss Voltage Output Range from ROSA (mV) – Voltage Input Range for Maxim 3264 (mV)

Additional VCSEL Purchase LC-TOSA 20 Free VCSELs Obtained

Introduction to Test Equipment

Tx Test Board Construction …

… And Immediate Correction Soldered Output Pins in Correct Locations

Tx Test Board Performance “Best” Eye Diagram PRBS7 Pattern Troubleshooting Necessary

Tx Test Board Troubleshooting Grand Conclusions Outputs and Inputs Reversed If one truly only learns through failure, we’ve learned a LOT already!

More Tx Test Board Work

Tx Test Board Quality Control Input in Input Output in Output

Tx Test Board Performance No attenuation PRBS7 Pattern Still not successful

Tx Test Board Conclusions Eye still not well defined Potentiometer has minor effect on performance Conclusion: Board permanently damaged from attempts to drive in reverse direction Result: If continued testing is necessary a new board is needed

Completed Tx Test Board – Take 2 ← ← Outputs

Tx Test Board Performance 0 dB 70 dB 10 dB ● PRBS7 Pattern ● 3 minute interval ● BER 0 dB)

Tx Test Board Performance (Continued) ● 70 db ● AC coupled ● 70 db ● Scaled down using potentiometer

Tx Test Board (Take 2) Conclusions Eye diagrams are very well-defined Potentiometer scales the eye dramatically Attenuation has minimal affect on eye Low BER rate suggests quality performance The Three are capable of building a working Tx board!

Tx & Rx Schematics Tx Rx

TxRx PCB Layout Conservative Agressive

Board 1A Construction

Board 1A Troubleshooting No Success with Tx or Rx High-Pitched Noise and a Smoking Ferrite Bead… Short Discovered Between Power Supply and Ground (Not from Layout)

Board 1B Construction The Three’s Tried-and-True Strategy: Start Over Results: Nothing Breaks During Testing!!!!!

Board 1B Troubleshooting Receiver Circuit Functions Perfetto Continuing Issues with Tx

Rx Test Setup

Rx Results PRBS7 Pattern 9 dB BER < 10^-11 5 minute duration Proper operation verified! Yay

Board 1B Transmitter Testing Left and Right Inputs to VCSEL Signals Want to Be Eyes… Not Quite There VCSEL Not Lasing An Attempt at Board 1Γ Tx Also Unsuccessful

Aggressive Tx Modifications Soldered all passives super carefully Used a 25k potentiometer to modulate I bias instead of 1k potentiometer Adjusted the VCSEL orientation for forward-biasing Adjusted pot values to safe levels before testing

Aggressive Tx Test Setup

Aggressive Tx Probing Laser Driver InputsLaser Driver Outputs Data - Data + Data - Data +

Aggressive Tx Results LASING!!!! Adjusting I mod and I bias showed improved results

Aggressive Tx Results (cont.) Working!!!!!!!!

Loopback Testing for Aggressive Design PRBS7 Pattern 7 dB Attenuation Super Yay Too Good to Be True? ….

Not This Time! Signal at 8 dB Attenuation is Lower Quality…As Expected BER < 0.0E-10 Removal of an Optical Fiber Produces a Lost Signal Verified Successful Completion of Gigabit Ethernet

Final Budget ItemSupplierPart #QtyUnit PriceTotal Amount Ferrite Chip InductorDigikey ND30 $ 0.12 $ 3.60 Power JackDigikeyCP-002APJCT-ND5 $ 0.81 $ 4.05 POT 1.0kOhmDigikey3296W-102-ND5 $ 2.50 $ POT 25kOhmDigikey3296W-253-ND5 $ 2.50 $ Resistor 115 OhmDigikey CCT-ND10 $ 0.08 $ 0.80 Resistor 100 OhmDigikey CCT-ND10 $ 0.08 $ 0.80 Resistor 24 OhmDigikeyRR12Q24DCT-ND10 $ 0.15 $ 1.51 Resistor 10 OhmDigikeyRR12Q10DCT-ND10 $ 0.15 $ 1.51 Capacitor pFDigikeyPCC103BNCT-ND100 $ 0.04 $ 3.66 SMAsJameco RFX10 $ 4.20 $ Gbps ROSAAdvanced Optical ComponentsHFD $ $ Gbps VCSELAdvanced Optical ComponentsHFE419x-5414 $ $ PCB Board FabExpress PCB 1 $ Shipping and MiscellaneousVarious $ Total $

Bill of Materials ProductVendorItem NumberQtyLarge Qty Price ($)Total Amount ($) POT 25.0K OHMDigikey3296W-253-ND RES 115 OHMDigikey CCT-ND RES 100 OHMDigikey CCT-ND RES 24 OHMDigikeyRR12Q24DCT-ND RES 10 OHMDigikeyRR12Q10DCT-ND CAP PFDigikeyPCC103BNCT-ND CONN PWR JACKDigikeyCP-002APJ-ND Ferrite Bead InductorDigikey ND VCSELAOCHFE419x ROSAAOCHFD Laser Driver ChipMaximMAX Limiting Amplifier ChipMaximMAX PCB BoardExpress PCB4 Layer Board Total $ 29.22

Final GANTT

The Three – Pratt Worthy!