Abstract: A system for determining a fly height includes a first head of a disk drive, a second head of the disk drive, a capacitive sensor circuit coupled to the first head and the second head, and a logic device coupled to the capacitive sensor circuit. The capacitive sensor circuit is configured to measure a first capacitance between the first head and the first disk, remove noise from the first capacitance using a second capacitance between the second head and the second disk, and based thereon determine a corrected first capacitance. The logic device is configured to determine the fly height between the first head and the first disk using the corrected first capacitance.

Abstract: A system for determining a fly height includes a first head of a disk drive, a second head of the disk drive, a capacitive sensor circuit coupled to the first head and the second head, and a logic device coupled to the capacitive sensor circuit. The capacitive sensor circuit is configured to measure a first capacitance between the first head and the first disk, remove noise from the first capacitance using a second capacitance between the second head and the second disk, and based thereon determine a corrected first capacitance. The logic device is configured to determine the fly height between the first head and the first disk using the corrected first capacitance.

Abstract: A method to determine a relative delay between a current-overshoot signal and a write data signal for a hard disk drive preamplifier, the method including using a memory element to strobe a test current-overshoot signal with a test data signal; counting a number of strobed transitions of the test current-overshoot signal; adjusting the delay based on the number of strobed transitions; setting a phase difference between the current-overshoot signal and the write data signal according to the delay; and using the memory element to strobe the current-overshoot signal with the write data signal.

Abstract: A disk drive is disclosed. The disk drive comprises a disk, a head configured to write data to and read data from the disk, and an actuator configured to position the head relative to the disk. The disk drive also comprises a die including internal circuitry electrically coupled to the head and a bypass trace electrically coupled to the actuator, wherein the internal circuitry comprises one or more preamplifiers and the bypass trace is electrically isolated from the internal circuitry.

Abstract: A shock resistant hard disk drive system employs a plurality of magnetic disks for recording data, a plurality of magnetic heads for performing input/output operation on the magnetic disks, with at least one of the magnetic heads being used as a servo head, a head-positioning mechanism for controlling the movement of the magnetic heads, a servo control mechanism or servo loop for opposing shifts in the location of the servo head, detecting device for detecting and measuring certain accelerations applied to the system, and filtering device for filtering the output of said detecting device and for providing the signal to the head-positioning mechanism. The detecting device detects and measures the magnitude of internal or external accelerations or shocks applied to the system, and provides the necessary signals to counter such accelerations.

Abstract: A current amplifier is provided with three active transistors of the same polarity type, which function to amplify the input signal at a wide range of frequencies, with low power consumption and low or no output crossover distortion. One transistor, in cooperation with the second transistor, significantly amplifies the current during one swing of the input singal while the third transistor is switched off, and switches on the third transistor just prior to a reversal of the input signal swing. By the proper and immediate biasing of the third transistor according to the circuit needs, low power consumption as well as low or zero output crossover distortion is achieved.