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Compact HDD motor controller also saves on power

Lexington, Mass.&#8212Citing an optimized chip partitioning scheme that extends battery life in consumer applications, STMicroelectronics' compact L7208 motor controller IC for 1.8-inch and sub-1.8-inch hard disk drives (HDDs), in an ultrathin LGA package, integrates its power FETs and all of the circuitry for driving the spindle motor and voice coil actuator.

The L7208, in bipolar-CMOS-DMOS (BCD) technology, includes the company's Smooth Drive pseudo-sinusoidal digital-drive technique for minimizing acoustic noise from the spindle motor, and a free-fall detector interface. Power consumption is reportedly extremely low in all operating modes, including a highly efficient sleep mode, to extend battery life. The controller's class AB output stage, delivering up to 0.5 amp peak current, has zero dead-band and minimal crossover distortion. The voice-coil section includes a 14-bit digital-to-analog converter (DAC) for current commands and load/unload circuits.

The spindle-motor section also includes circuits for spindle-current limiting, start-up position sensing, and spindle braking during power-down. The L7208 is register controlled, and connects to the host system through a serial bus running at up to 50 MHz. Auxiliary functions integrated on the chip include an internal isolation FET, a 10-bit ADC, programmable voltage regulators, and a shock sensor.

Click here to access the product data brief. Samples of the L7208 will be available in October, priced at $15.

STMicroelectronics , 1-781-861-2650, www.st.com

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