Driver chip power three different laser diodes

The ATR0881 is a laser diode driver IC for use in combination HD-DVD/Blu-ray, DVD and CD drives.

Available now from Atmel Corp, the ATR0881 is a laser diode driver IC for use in combined HD-DVD/Blu-ray, DVD and CD drives.

The device is housed in a 4 x 4mm QFN24 package, making it the industry's smallest laser diode driver solution and especially suited for small slim drives used in notebook computers as well as for half-height drives in desktop PCs and consumer DVD recorders.

The ATR0881's QFN housing is a lead-free paddle-up package with the exposed paddle on top to improve heat dissipation.

A bottom-located exposed paddle, as found in conventional QFN packages, causes difficulties due to its inaccessibility for circuit design, particularly in optical pick-up products.

This design restriction is eliminated with Atmel's ATR0881.

Although the ATR0881 has three outputs for connecting three laser diodes - a blue (HD-DVD/Blu-ray), a red (DVD) and an infra-red (CD) - it still fits into the same small 24-pin package used by Atmel's well-known laser diode drivers for two-output combined DVD and CD drives.

The ATR0881 is the first of its kind with a serial interface.

Whereas conventional laser diode drivers have a fixed gain between input and output, the gain of each of the ATR0881's five channels can be individually programmed using the serial interface.

As a result, the ATR0881 is extremely flexible and avoids complete redesigns if gain requirements change.

The serial interface can also be used to set all parameters of the integrated oscillator including frequency, amplitude, and spread-spectrum settings.

Current laser diode drivers need up to six external resistors and pins to set the oscillator parameters.

With the ATR0881, these additional resistors are not required; thus the overall bill of material is reduced.

The requirement for oscillator frequency accuracy is very high to ensure low electromagnetic interference.

Due to resistor tolerances, common laser diode drivers enable a maximum accuracy of +/-10%.

In contrast, designs using the ATR0881 achieve a frequency deviation of less than +/-5% thanks to the laser diode driver's integrated frequency counter.

Compared with competing devices, the ATR0881 can optionally be set to a special synchronisation mode, which synchronises all write channels to the second channel, thus enabling the generation of very sharp output pulses for increased data security.

Samples of the ATR0881 in 4 x 4mm QFN24 paddle-up packages are now available.

Pricing starts at US $5.00 in quantities of 10,000.

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