Low-noise single-coil fan driver IC with built-in current limiting

Aimed at the development of energy-efficient cooling system designs, Melexis has introduced the MLX90297, a new 600mA single-coil fan driver IC. Based on the proven MLX90287, the newcomer integrates a high-sensitivity Hall-effect sensor with two powerful half-bridge output stages. In addition to the minimum speed setting incorporated into the MLX90287, the speed curve of MLX90297 can also be tuned through inclusion of just one extra resistor. The soft start and soft switching mechanisms have been further refined to achieve industry-leading acoustic noise levels, as well as low vibration at higher speeds, without maximum motor torque being sacrificed. The reduced driver resistance (RDSon) of the MLX90297, in combination with the built-in current limiting, allows application of this fan driver to fans with coil resistances substantially lower than 10Ohm. The electro-static discharge (ESD) performance has been further enhanced to achieve 9kV HBM. The device is offered in a straight lead SOIC8 package. A DFN10 3mm x 3mm exposed pad package option is also available for very small fans and fans with motor currents up to 600mA, says the company. Dirk Leman, product line manager for fan drivers, Melexis, said: ”Our All-In-One MLX90287 in straight lead SOIC8 product has been received very warmly by the fan driver market. It lowers the total bill-of-materials cost and the complexity of the PCB design significantly by reducing the number of discrete components involved. Previously up to 22 resistors and transistors might have been needed for a TSSOP16 fan driver with an external hall sensor. Now just 2 resistors, and one decoupling capacitor are required for a SOIC8 fan driver solution. “The MLX90297 is a natural evolution based on customer feedback. It offers a highly optimized solution for demanding high volume applications like VGA and CPU cooling, as well as white goods, and even low end server applications.“ With our world class expertise in Hall Effect sensing and motor control IC design, Melexis continues to strive to deliver better fan drivers at a lower cost, which is imperative in order to stay competitive in the fan driver market.“