National Semiconductor, represented by Arrow , has introduced laser diode drivers (LDDs) that will allow desktop and notebook manufacturers to slash write and rewrite times by up to 50 percent. The new drivers will enable consumers to burn full 4.7-Gbyte DVD discs in approximately 15 minutes. These LDDs, part of National’s high-speed LMH family of amplifiers, were specifically designed for combination DVD/CD recorder optical storage devices used in desktop, notebook and consumer DVD video recorders.
The LMH LDD products claim to allow manufacturers of optical pickup units (OPUs) to provide OEMs and consumers with the fastest DVD/CD recorders on the market. The high speed requirements of driving the signal from the controller chip to the OPU are met by integrating the LVDS interface into the driver. National’s VIP10 process technology provides a switching rate of less than 0.5 ns, enabling, what is said to be, the fastest write and rewrite times for optical recording. This combination of LVDS interface and fast switching rates is said to offer users the highest-speed laser diode drivers available.
The market for DVD optical storage devices is growing rapidly as consumers turn their computers into entertainment vehicles. “We have the technology roadmap in place to produce next-generation products that will achieve a 12x write and 8x rewrite capability,” says Erroll Dietz, product line director for National’s Amplifiers group.
National’s new LMH LDD chip operates on a single 5 V supply with fast switching rate of less than 0.5 ns. The device is dual-output capable of driving the 780 nm CD laser diode or the 650 nm DVD laser diode. An integrated high frequency modulator (HFM) oscillator offers selectable frequency and amplitude setting via external resistors, with a 200 MHz to 600 MHz range. The amplitude is scalable to 100 mA peak-to-peak. Four independent current channels are capable of 400 mA maximum total output current.
National’s laser diode drivers are based on the VIP10 (vertically integrated PNP) process - a high speed, dielectrically isolated, complementary bipolar IC process that utilises deep trench technology on a bonded wafer for dielectric isolation and high-speed amplifier performance.