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 MAX Gbps 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 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