Laser diode support top-speed DVD/CD combos

A new range of laser diode drivers are the first to support x16 DVD and x52 CD write/rewrite speeds for the next-generation of optical disc drives used in high-speed DVD/CD combination recorder units.

A new range of laser diode drivers are the first to support x16 DVD and x52 CD write/rewrite speeds for the next-generation of optical disc drives used in high-speed DVD/CD combination recorder units.

Powered by Zarlink's laser diode drivers, DVD/CD recorder units will be able to write a 4.7Gbyte DVD - the equivalent of a 2h movie - in under 6min.

In comparison, it currently takes an unacceptable 1.3h to write the same movie at x1 speeds.

The market for consumer high-speed DVD/CD recorders and computer optical disc drives is set to grow rapidly, as new high-speed recorder devices offer more convenience and a broader range of applications come to market.

Zarlink research forecasts approximately 100 million DVD/CD recorder units will be shipped in 2005.

In the home, DVD/CD recorders are an increasingly standard feature on personal computers, as consumers burn digital camera, digital camcorder, and music and movie files onto optical discs.

DVD recorders are also replacing traditional videocassette recorders, while the next generation of personal video recorders (PVRs) will incorporate DVD record functionality.

In the office, optical discs are increasingly popular for data storage due to their small size and tremendous storage capacity.

"Speed is the key driver in the DVD/CD recorder market, with manufacturers of optical pickup units demanding components that support the highest speeds possible at an acceptable cost", said Peter Minett, Product Marketing Manager, Consumer Communications, Zarlink Semiconductor.

"The ZL40510/1 laser diode drivers offer the first commercially available devices to efficiently meet these demands, with high-current write channels and industry-leading switching times".

Laser diode drivers are electrical-based devices that convert voltage into current, which the laser then converts into a light pulse to burn information onto an optical disc.

The ZL40510/1 laser diode drivers include two four-channel devices capable of driving separate 650nm DVD and 780nm CD lasers in a combination DVD/CD unit.

The premier ZL40510 device supports up to x16 capabilities for high-speed DVD recorder systems and optical disc drives, while the ZL40511 is suited for existing slower speed x4 and x8 systems.

Both devices include three 500mA write channels with 240x current gain - the industry's most powerful single-channel write output - and one 150mA low-noise read channel with 100x current gain.

With high-current output write channels, the ZL40510/1 laser diode drivers can write x16 DVDs and x52 CDs using a single channel.

In comparison, competing devices require designers to combine several lower-current channel outputs to reach the power requirements necessary for high-speed DVD/CD write and rewrite.

This approach is more sensitive to timing inaccuracies between the combined channels, also known as skew, resulting in slower overall system speed and corrupted optical discs.

The ZL40510/1 devices features the industry's fastest high-current switching times, with guaranteed rise times of 1.2ns and fall times of 1.4ns, and typical performance of 0.9ns rise time and 1.1ns fall time over the full current range.

Faster rise and fall times translate into fast DVD/CD write and rewrite speeds for users.

The ZL40510/1 laser diode drivers deliver the industry's fastest propagation delay of 1.4ns and the smallest channel-to-channel skew of 50ps.

The combined ability to deliver full write power with a single channel in 1ns edge speed, and switch between write, erase, cooling and read levels within 50ps timing skew, offers manufacturers a low cost route to optical disc drivers delivering x16 DVD write and rewrite speeds.

Providing ultrastable performance at a maximum junction temperature of 150C, the high heat tolerance of the ZL40510/1 devices simplifies the design of the optical pickup unit and helps ensure reliable operation.

The devices also include a high performance, low harmonic, switched oscillator with a programmable frequency range of 200 to 500MHz and 20 to 100mA peak-to-peak.

By suppressing laser noise when reading optical discs, the oscillator helps deliver superior audio and video quality.

The ZL40510 laser driver diode's read and write channels are controlled by an integrated LVDS interface, which provides low-noise, high-speed data transmission over ribbon cables between the controller chip and the optical pickup unit.

The LVDS interface allows the write strategy to be inexpensively and efficiently incorporated into the motherboard chips, reducing the overall cost of the optical pickup unit.

Competing solutions place the write strategy on the optical pickup unit, leading to increased design costs and a limited component choice for manufacturers.

The ZL40511 driver includes the same performance features as the ZL40510 driver, but with a CMOS logic-compatible control interface to cost-effectively support existing slower speed x4 and x8 DVD/CD recorder units.

Global manufacturers are currently evaluating the ZL40510/1 laser diode drivers for use in high-speed optical pickup units.

Zarlink's devices meet x16 DVD write and rewrite standards currently under development by the DVD Alliance and DVD Forum.

The ZL40510/1 drivers are now in volume production, and are available in 4 x 4mm, 24-pin QFN (quad flat no-lead) packaging.

In quantities of 100,000, the ZL40510/1 are priced at US $0.65 each.

Evaluation boards for the devices are available.

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