Communications: Blue Laser Driver Extends DVD Write Speed

The MAX3701 drives common-cathode blue lasers in high-end DVD player/recorders and high-density optical drives. It contains a programmable current source for generating the laser bias current with five different levels up to 200 mA p-p. Also, it can achieve an edge speed as short as 900 ps with up to 8% overshoot. Incorporated in the driver are a transimpedance amplifier (TIA) and a sample-hold circuit, which can be used with an external photodiode to monitor signal output and provide closed-loop feedback control if desired. An on-chip programmable oscillator can generate signals in the 200- to 600-MHz range over a 15- to 150-mA p-p range. The MAX3701 comes in a 32-pin 5- by 5-mm QFN package. Price is $1.95 in 10,000-unit quantities.