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 MAX32871.25Gbps Common-Cathode configuration3.5 to 5.5 supply voltage30mA laser modulation current

Description of Components

Composition of Laser Driver

Bias generator with APC

Laser modulator

Safety circuit

Power-on reset (POR) circuit

Bias GeneratorSpecifications

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 CircuitryAPC laser safety using local feed-backOpen Fiber Control (OFC)Dual enable and fault inputsFour 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 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