Transcript Design Presentation

1394b Gigabit Ethernet
The transmitter Group
(G8)
Design Proposal
Mubin Ansari
Zubair P. Siddiqui
February 14, 2002
MAX3287 Evaluation Kit
Specifications
Surface-mount Demonstration board
Allows optical and electrical evaluation
of MAX3287
1.25Gbps
 Common-Cathode configuration
 3.5 to 5.5 supply voltage
 30mA laser modulation current

Description of Components
Composition of Laser Driver
Bias generator with APC
Laser modulator
Safety circuit
Power-on reset (POR) circuit
Bias Generator
Specifications
Power-control Amplifier
Smooth-start circuit
Window Comparator
BIASDRV output drives an
external PNP
Monitor diode (MD)
APC circuitry for maintaining
constant laser output
Modulation Circuitry
Specifications
Input buffer
Current generator
High current switch
Current up to 30mA
into a 25Ω load by
these components
Safety Circuitry
APC laser safety using
local feed-back
Open Fiber Control (OFC)
Dual enable and fault
inputs
Four different modules




Pulse Generator
Fault Detection
Shutdown
Latched Fault output
Safety Circuitry (cont’d)
Pulse Generator

Disables the safety
system during startup
Fault Detection


Monitors all critical
nodes
Laser shutdown when
fault is triggered
Shutdown

Dual bias shutdown
mechanisms
Latched Fault Output


Latches whenever a
fault is detected
Stays latched until reset
or enable pin toggled
Programming the Bias
Current
Discrete components

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PNP Q1
Laser diode
MD
Capacitor (Cbiasdrv)
rejects power supply
noise
Design Evaluation Board
Proposal
Similar to the MAX3287 Evaluation board
Optical and Electrical connections for diodes and
ground
SMA connectors
MAX3287 chip
Main objective: Cost reduction and increased
efficiency