Motor Controller Drivers – for mobile hard disk drive applications

Atmel announced a spindle/VCM motor controller/drivers product family. AT78C7005 and AT78C7015 are CMOS monolithic devices that integrate spindle and VCM (Voice Coil Motor) controllers as well as power stages into one chip. Both devices are optimized for mobile platforms of 2.5″, 1.8″, 1″ and 0.85″ hard disk drives. The AT78C7005 has an auto detect supply voltage at power-up that operates from a 3.3V or 5.0V, which enables it to run on a battery or charger. Optimized power consumption is one of the key elements when designing for mobile disk drives. A programmable 10-bit DAC offers very accurate spindle speed and a 1A current capability with RON = 1 Ohm. The VCM's programmable 14-bit DAC combined with a 10-bit ADC provide speed control ramp load/unload. Power-off retract is realized by the use of a 9V charge-pump. While data rate increases constantly the new applications within the consumer electronics are adopting the use of micro drives (1″ and 0.85″ platforms). Many consumer applications are using micro drives, some making transition from 2. 5″, to 1.8″ and even 1″ and 0.85″ form factors. Small mobile drives can rotate at higher speeds, yielding higher data rate. They also need to be low voltage for longer battery life and lower battery size and weight to provide durability against physical shock. Both AT78C7005 and AT78C7015 conveniently support these functions by integrating special features that protect against data loss from decaying voltage while supporting a small design foot print. The AT78C7005 operates from a 3.3V or 5.0V while AT78C7015 runs on a single supply of 3.3V and has the best power saving modes for maximum battery life, 9mA in normal run mode. This makes it ideal for mobile hard disk drive companies manufacturing. On-chip 1.8V, 2.5V and “3V regulators are designed into both devices to provide power to other chips in the system. A precision low-voltage detection circuit monitors the power supply and initiates VCM retract at voltage fault condition, which prevents data corruption due to the low battery or power loss. Atmel Corp Europe, 78054 St Quentin-en-Yvelines, France.

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