Abstract: Disclosed is a lead frame and a semiconductor device including the same. The lead frame is provided with a die pad, and first, second and third lands sequentially arranged on an outer circumferential edge. The lead frame can separate the first and second lands or the die pad and the first land using a plating layer formed on the lead frame as a mask, instead of using a separate mask by etching after the application of the encapsulant. As a result thereof, a plurality of lands can be formed at low cost, in comparison with a conventional method. Additionally, the first, second and third lands are exposed to the outside through a lower portion of an encapsulant, and can be surface mounted on an external device through the first, second and third lands.

Abstract: A method and apparatus for estimating position and speed of a read/write head in a disc drive, based upon the back EMF of the voice coil motor involves estimating the voltage across the voice coil motor and estimating the voltage across a current-sensor resistor in the voice coil circuit, preferably with a differential amplifier. Further, a coil resistance voltage is estimated by measuring the voltage across the current-sensor resistor with a differential amplifier and amplifying the voltage across the current-sensor resistor by a gain value. Finally, the combined voltage across the current-sensor resistor and the characteristic coil resistance is subtracted from the voltage across the voice coil motor, yielding the back EMF of the voice coil motor. The back EMF is representative of head velocity which may be integrated to yield position. Accordingly, the back EMF can be used to control the speed and position of the read/write head.