Addressing micro concerns with macro performance

Ieper, Belgium – 12th of June 2007 - Melexis announces a new member in the Omnipolar™, Micropower Hall effect switch family. The MLX90248 employs CMOS technology to deliver a non-contact magnetic switch with microwatt power consumption. Typical applications are found in flip, slide and clamshell portable handsets, PDA’s and personal entertainment devices.

The MLX90248 detects the opening action to wake up the device main functions and prepare for immediate use by the operator. The newest member, Part Number MLX90248ELD, is in a low profile Ultra-Thin QFN package that enhances the benefits of pole-independent, micropower performance by providing for more compact system design. The device also exhibits very high magnetic sensitivity with accurate and reliable performance over the operating range due to advanced dynamic offset cancellation technique incorporated on-chip. The magnetic sensitivity of the MLX90248 is Omnipolar™ meaning that it can be activated by either a North magnetic field or a South magnetic field. The device switches ON in the presence of sufficiently strong magnetic field (Bop) facing the marked side of the package. The output switches OFF in the absence of a magnetic field (Brp).

In applications Omnipolar™ reduces the efforts for magnetic design to simply matching the specified thresholds (Bop/Brp) irrespective of polarity. In production, it enables a process that is more efficient by eliminating the need to align the activating magnet during assembly. MLX90248 integrates very high sensitivity Hall sensor with maximum operating point of 6mT and minimum release point of 0.5mT. System costs are reduced as a relatively small and inexpensive magnet is sufficient to trigger the IC.

Low current consumption
Many sensor applications are battery-operated or have rigid requirements towards power consumption. The MLX90248 combines low supply voltage capability (2.5V ~ 3.5V) with low average current consumption (8µA @ 2.5V). The circuit employs a clocking mechanism to cycle power to the Hall element and analog signal processing units. Sensing takes place every 70ms (maximum). During this period, the internal logic triggers the device into ‘AWAKE’ mode for an average of 85µs in order to sample possible change in magnetic field. Then the flux from the Hall element is compared against the predefined thresholds (Bop/Brp) and the output state is changed in accordance to thresholds. For the rest of the period MLX90248 is in ‘SLEEP’ mode with the output being latched to its previous state. This SLEEP/AWAKE strategy drives IC microwatt performance (less than 18µW @ 2.5V) while reliability and accuracy of magnetic field detection are maintained. Due to low consumption MLX90248 fits well into power-critical applications and facilitates increase of operating time between battery recharges (at equal other conditions).

Package
To date the MLX90248 has only been delivered in Thin SOT-23 (customer PN MLX90248ESE) package. The device is now also provided in a Chip Scale Package option, the smallest packaged IC configuration available. The CSP saves valuable PCB and housing space allowing smaller integration or freeing space for other features and functions. The footprint of the new Ultra-Thin QFN (Quad Flat No leads) package is only 3mm2 (1.5 x 2mm) with 0.43mm maximum thickness. This is particularly important in applications such as handhelds and portables where the demand is unceasingly for miniaturisation and ultra-slim designs.

Applications
Initial applications of the MLX90248 have been in mobile handsets detecting open/close and turning on/off the main functions. Melexis pioneered micropower segment with first deliveries dating back in 1998. Ever since, the MLX90248 solid design and reliable performance along with Melexis’ technical support and uncompromised quality are winning more and more recognition. Samsung, a leading consumer electronics manufacturer, relies on the Omnipolar™ Micropower Hall effect switch and integrates it in their latest award-winning designs. The MLX90248 has broadened its application reach into many more electronic gadgets such as cameras and camcorders (screen rotation detection), notebooks and portable players (screen on/off), camera lens cover and pop-up flash (on/off) and various others. The journey is well on the way as the well-known Hall effect switch continues to tackle central design considerations of simplicity and flexibility through omnipolar magnetic behavior; low power consumption based on microwatt operation; small footprint and weight based on new low profile Ultra-Thin QFN package. System costs are also reduced summing up all the advantages MLX90248 commands.

Availability
Engineering samples of MLX90248ELD (UTQFN) are available now. Start Of Production (SOP) is scheduled for end of Q2 2007. The MLX90248ELD is priced at Euro 0.251 for quantity of 50k. The MLX90248ESE (TSOT) is also in mass production and samples are available as well. The MLX90248ESE is priced at Euro 0.238 for quantity of 50k.