Transcript Final Presentation

Optical Gigabit Ethernet
Group F.O.R.E.
Final Presentation
Chris Abbott, Ronen Adato, David Larado
4/21/2005
Overview
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Purpose was to build physical layer of optical
gigabit transceiver
Selected active components based on
availability, connectorization, quality
Designed and laid out two transceiver printed
circuit boards
Built and tested boards
Compiled prototype budget and productionscale bill of materials
IEEE 803.z Standard
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Extinction Ratio
Eye-safe power level
Criteria for testing
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Definition of Bit Error Rate
Use of eye as guideline, but not for formal
test
Test Board
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Built test board to learn soldering and
testing techniques
Soldered Test Board
Test Setup (To oscilloscope)
Test Board Results
No resistance/Full Setup
High resistance/Full Setup
<-- High resistance /
test board only
Ideal resistance /
test board only -->
Ideal resistance/Full Setup
VCSEL Selection
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Criteria for selecting VCSEL:
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Good performance (slope efficiency,
threshold current)
Availability
Cost
Connectorization (SC over LC)
VCSEL Performance Analysis
AOC vs Lasermate
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Performance Similar
Lasermate costs more in small
quantities (costs comparable in bulk)
AOC is LC connectorized, Lasermate is
SC
Chose Lasermate due to SC
connectorization (no patch cords)
ROSA vs. PD
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Past years have used PDs
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ROSA contains TIA inside package
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Requires external TIA
Possible reduction in noise
Easier layout
Comparable prices, easier to find
Leading PD vendor too expensive
Chose ROSA
ROSA Selection
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Lasermate RSC-P85P416 1.25 Gb/s SC ROSA
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SC connectorized ROSA
Costs:
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2-3 = $36.00/unit
>10,000 = $6.00/unit
Optical Link Budget
Schematic Design
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Schematics derived from:
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Maxim datasheets
Maxim application notes
Past group’s work
Used three element power supply filters
Conservatively coupled Vcc and ground with
decoupling capacitors
Designed for common anode VCSEL
configuration
Transmitter Schematic
Receiver Schematic
PCB Layout Considerations
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Kept traces as short as possible to
prevent transmission line behavior
Avoided sharp corners on high-speed
lines (used 45° angles when needed)
Kept high-speed differential lines
symmetrical
Effectively separated ground plane of
transmitter and receiver
Conservative Layout
Aggressive Layout
Conservative Board 1
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Soldered all
components and
tested the Rx circuit
for a clear eye
SMA/QMA fiasco
prevented BER
testing for the Rx
circuit, and any Tx
circuit testing
Rx Circuit Test Setup
Eye Produced by Rx Circuit, Signal PRBS 7
Conservative Board 2 Rx
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Reused SMAs from
test board, soldered
a new board
The Rx circuit failed
to produce an eye
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Rx Circuit Waveform Measured Before LA
It was determined
that the LA
(MAX3264) had been
damaged
Rx Circuit Waveform Measured After LA
Conservative Board 2 Tx
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Soldered board, but had to reuse VCSEL
from conservative board 1
Voltage drop across VCSEL was 5V
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VCSEL could be damaged
VCSEL could be connected incorrectly
Removed VCSEL and checked behavior
by pin-pin resistance
Aggressive Board 1
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Decided to try Emcore VCSEL on
aggressive design to get Tx working
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Aggressive Tx very similar to conservative
Tx
Made sure we knew how Emcore fit into
board
Aggressive Board, TxRx
We varied the
attenuations with,
the transceiver:
 4dB
7dB
Using different
combinations of
the optical
attenuators, we
were able to try
these also:
9dB
12dB
Aggressive Board, BER
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BER of less than 10^-9 when each
signal was tested
PRBS7, at least 5 minutes test runtime
Financial Budget
Financial Budget
Part Description
.01μF Ceramic Chip Capacitor
49.9Ω Chip Resistor
100Ω Chip Resistor
115Ω Chip Resistor
150Ω Chip Resistor
50kΩ Potentiometer
1kΩ Potentiometer
Ferrite Bead Inductor
Right Angle PCB SMA Jack
Surface Mount Power Jack
850nm, 1.25Gb/s SC VCSEL
850nm, 1.25Gb/s SC ROSA
PCB Board
Vendor
Digi-Key
Digi-Key
Digi-Key
Digi-Key
Digi-Key
Digi-Key
Digi-Key
Digi-Key
Newark InOne
Digi-Key
Lasermate
Lasermate
Express PCB
Stock Number Quantity/Link Unit Price
Quantity
Cost
399-1091-1-ND
18
$ 0.04200
100 $
4.20
311-49.9CCT-ND 1
$ 0.08000
10 $
0.80
311-100CCT-ND 2
$ 0.08000
10 $
0.80
311-115CCT-ND 1
$ 0.08000
10 $
0.80
311-150CCT-ND 1
$ 0.08000
10 $
0.80
3362P-503-ND
1
$ 0.83000
6 $
4.98
3362P-102-ND
1
$ 0.83000
6 $
4.98
490-1034-1-ND
6
$ 0.12000
40 $
4.80
07J2532
4
$ 4.51000
6 $
27.06
CP-002APJCT-ND1
$ 0.81000
2 $
1.62
TSC-P85A426-2 1
$ 32.00000
3 $
96.00
RSC-P85P416
1
$ 36.00000
3 $
108.00
Custom
1
$ 59.95000
1 $
59.95
Shipping: $
29.00
TOTAL
$
343.79
Bill of Materials (BOM)
Bill of Materials -Cost per Board at Production Capacity
Part Description
.01μF Ceramic Chip Capacitor
49.9Ω Chip Resistor
100Ω Chip Resistor
115Ω Chip Resistor
150Ω Chip Resistor
50kΩ Potentiometer
1kΩ Potentiometer
Ferrite Bead Inductor
Surface Mount Power Jack
Laser Driver
Limiting Amplifier
850nm, 1.25Gb/s SC VCSEL
850nm, 1.25Gb/s SC ROSA
**PCB Board
Vendor
Digi-Key
Digi-Key
Digi-Key
Digi-Key
Digi-Key
Digi-Key
Digi-Key
Digi-Key
Digi-Key
Maxim
Maxim
Lasermate
Lasermate
Express PCB
Stock Number
Quantity Per Link Production Cost
399-1091-1-ND
18 $
0.00988
311-49.9CCT-ND
1 $
0.01682
311-100CCT-ND
2 $
0.01682
311-115CCT-ND
1 $
0.01682
311-150CCT-ND
1 $
0.01682
3362P-503-ND
1 $
0.36000
3362P-102-ND
1 $
0.36000
490-1034-1-ND
6 $
0.06400
CP-002APJCT-ND
1 $
0.53800
MAX3287
1 $
4.30000
MAX3264
1 $
4.30000
TSC-P85A426-2
1 $
6.95000
RSC-P85P416
1 $
6.00000
4 Layer Board
1 $
5.71950
TOTAL
**The Express PCB pricing formula is $260+.66*Number of boards*Square inches
per board+$1.00*Number of boards w ith a 25% discount for quantities of over 2000
Cost (10k Links)
$
0.17784
$
0.01682
$
0.03364
$
0.01682
$
0.01682
$
0.36000
$
0.36000
$
0.38400
$
0.53800
$
4.30000
$
4.30000
$
6.95000
$
6.00000
$
5.71950
$
29.17
Gantt Chart
Future work
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Get Lasermate VCSEL working
Write final report
Conclusions
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Project was a success
Learned about entire design process