Hgst Netherlands, B.v.

Western Digital Technologies, Inc.

Other

Rehan Ahmed Zakai

John Thomas Contreras

Samir Y Garzon

Bruce Alvin Gurney

Patrick Braganca

Richard Leo Galbraith

Erhard Theodor Schreck

Bruce Alexander Wilson

Neil Smith

Albert John Wallash

Joey Martin Poss

Nobumasa Nishiyama

Sayed Mobin

Barry C Stipe

Weldon Mark Hanson

Lidu Huang

Sukumar Rajauria

Yiduo Zhang

Shen Ren

Edgar Dennis Rothenberg

Srinivas Rajendra

Tzong-Shii Pan

Venkatesh Ramachandra

Jian Zhu

Xinzhi Xing

Ikuya Tagawa

Kazuhiro Nagaoka

Robert Lee Smith

Eiji Soga

Keyu Pi

Daniel Oh

Various illustrative aspects are directed to a data storage device comprising a disk; a read/write head configured to read data from and write data to the disk; a laser diode configured to heat an area of the disk near the read/write head; and one or more processing devices configured to preheat the laser diode to a target temperature associated with a write operation, wherein the preheating comprises applying (e.g., using a preamplifier) at least one forward bias pulse to the laser diode, wherein a corresponding duration of the at least one forward bias pulse is shorter than a duration of a turn-on delay for the laser diode; and initiate a write operation for writing data to the disk, based at least in part on the preheating.

Dark laser heating by positive pulse biasing in heat assisted magnetic recording

The present disclosure generally relates to apparatuses and methods for transmission line termination. In one embodiment an apparatus includes a stack of uniform memory dies and a storage controller. Each uniform memory die in the stack of uniform memory dies couples to a transmission line in series through wire bonds to form a transmission path. Each memory die includes an on-die termination resistance circuit connected to the transmission line. The on-die termination resistance circuit provides a minimum termination resistance. The storage controller addresses a target uniform memory die of the stack of uniform memory dies for an operation. The storage controller enables the on-die termination resistance circuits of a plurality of uniform memory dies along the transmission path. The storage controller transmits a data signal for the operation to the target uniform memory die with the on-die termination resistance circuit enabled for the plurality of uniform memory dies.

Distributed grouped terminations for multiple memory integrated circuit systems

An active termination circuit comprising an input node connected to a transmission line, a first transistor, and a second transistor. The transmission line supplies a signal to the input node. The first transistor is diode connected between a high voltage supply and the input node. The first transistor terminates the signal when the signal is at a low logic level. The second transistor is diode connected between the input node and a low voltage supply. The second transistor terminates the signal when the signal is at a high logic level.

Active low-power termination

A circuit interconnect for high bandwidth and high die-count memory stacks. The circuit interconnect may include a first ground trace, a first signal trace, a second ground trace, and a second signal trace. The first ground trace may reside in a first layer of a multilayer printed circuit board. The first signal trace may be positioned adjacent to the first ground trace within the first layer. The second ground trace may reside within a second layer of the multilayer printed circuit board. The second signal trace may be positioned adjacent to the second ground trace within the second layer.

Printed circuit board compensation structure for high bandwidth and high die-count memory stacks

Embodiments disclosed herein generally relate to a method for monitoring optical power in a HAMR device. In one embodiment, the method includes enhancing a thermal sensor bandwidth through advanced electrical detection techniques. The advanced electrical detection techniques include obtaining calibration waveform data for a thermal sensor by calibrating the thermal sensor, obtaining real-time waveform data for the thermal sensor that may deviate from the calibration waveform data, updating the calibration waveform data to include the real-time waveform data, repeating obtaining real-time waveform data and updating the calibration waveform data during writing operations. By updating the calibration waveform data, the bandwidth of the thermal sensor is determined by a fixed sampling time interval, and the thermal sensor rise time to steady state would not be a limitation to its response time.

HAMR thermal sensor with fast response time

An active low-power termination circuit includes a first leg of a pair of transistors connected in series between the high supply level and ground, where the termination input is at a node between the transistors of the first node. A second leg uses a feed forward mechanism to control the voltage levels on the control gates of the transistors of the first leg. The second leg includes a second pair diode connected transistors, each of which is has its control gate connected to the control gate of the corresponding transistor in the first leg. A variable current source connected in series with the transistors of the second leg and is controlled by the output of a difference amplifier that has one input connect to an intermediate node of the second leg and a second input connected to a reference level intermediate to the high supply level and ground.

Disclosed herein are suspension assembly structures for data storage devices that include physical or virtual crossovers of the pairs of differential signal traces to improve immunity to crosstalk and other interference. In an embodiment, the suspension assembly structure comprises a first trace for carrying a first component of a current to a differential transducer on a slider, a second trace for carrying a second component of the current to the differential transducer on the slider, and third and fourth traces for providing a differential write current to a writer of the data storage device, wherein the first trace physically crosses over the second trace at a first distance from a tail of the suspension assembly structure.

Suspension adjacent-conductors differential-signal-coupling attenuation structures

A data storage device is disclosed comprising a head actuated over a disk, wherein the head comprises a first sensor element and a second sensor element. When configured into a first single-ended mode, a bias signal is applied to the first sensor element to generate a first single-ended output signal based on a response of the first sensor element, and when configured into a second single-ended mode, the bias signal is applied to the second sensor element to generate a second single-ended output signal based on a response of the first sensor element. When configured into a differential mode, the bias signal is concurrently applied to the first sensor element and the second sensor element to generate a differential output signal based on a response of the first sensor element and the second sensor element.

Data storage device employing multi-mode sensing circuitry for multiple head sensor elements

Interconnect and preamplifier designs are described for use in a disk drive with a common signal return lead system that interconnects a plurality of read transducers (readers) in a slider through the suspension to the preamplifier mounted on the actuator. Preamplifier embodiments have an isolated differential amplifier for each of the plurality of readers in the slider. The set of signal traces in the suspension include a common signal return lead for the plurality of readers in the slider. A preamplifier circuit design according to an embodiment of the invention includes isolated amplifiers for each reader with a separate bias source and power supply isolation elements for both power supply polarities for reduced crosstalk signal and noise between amplifiers.

Disk drive with preamplifier with isolation for multiple readers in a slider with a common return signal

An interconnect between the read/write circuitry and the read/write head in a magnetic recording hard disk drive (HDD) for two-dimensional magnetic recording (TDMR) has the read sensor signal lines located on a lower level of a bi-level structure of conductive lines. Common return lines are located on an upper level above the signal lines and on the lower level between the signal lines. All of the return lines on the upper level are connected to one another by cross-connect lines, and vias are located along the interconnect and connect the upper return lines with the lower return lines and with the ground plane of the interconnect's electrically conductive substrate. The interconnect is a coaxial-like interconnect because the return lines are located around each signal line and thus shield each signal line from the other signal lines, much like the outer conductive shield of a coaxial cable.

Integrated lead suspension (ILS) for two-dimensional magnetic recording (TDMR) disk drive

A 'split-substrate' design is described for the metal ground layer in the suspension for a slider for use in a disk drive that reduces crosstalk from signals being transmitted on the conductive traces and allows externally induced interference to be shunted away from sensitive traces along selected portions of the suspension. In embodiments of the invention a slit formed in the metal ground layer to provide two parallel ground paths respectively on the left and right sides of the selected portion of the suspension. By positioning interference signal generating traces like writer traces on one side of the slit, that side becomes the noisy ground path leaving the other side as a 'quiet' ground path. The shape, positioning and grounding of the split substrate structure can shunt return/ground currents created by external RFI into the noisy leg and thereby shield the quiet leg.

Suspension design with split substrate for improved interference signal immunity

A disk drive dynamic wave shaper (DWS) write driver includes a write current generator that produces a baseline output current for the write current pulses and an overshoot current generator that produces an overshoot current with different values. The overshoot current is added to the baseline current, with the value of the overshoot current amplitude (OSA) being selected in response to the frequency of transitions in the write data signal. The write driver includes logic circuitry that detects the pattern of transitions. Transitions that are immediately followed by a transition will receive a larger-than-nominal OSA1, transitions that are not immediately followed by a transition and that are not preceded by a long sequence of non-transitions will receive a nominal OSA2, and transitions after longer sequences of non-transitions will receive a smaller-than-nominal OSA3.

Magnetic recording disk drive with write current overshoot amplitude (OSA) responsive to data transitions

A method, apparatus, and system are provided for implementing noise based detection of spin-torque oscillator (STO) power on for microwave assisted magnetic recording (MAMR) hard disk drives (HDDs). A low frequency noise generated by a spin-torque oscillator, such as noise in a frequency range between 10 kHz and 100 MHz, is detected. The detected STO noise is compared to a predefined threshold to identify STO power on operation.

Implementing noise based detection of spin torque oscillator power-on in microwave-assisted magnetic recording (MAMR) hard disk drives

A multiple-segment transmission line in a hard disk drive enables a wider optimization range of the slope, duration and amplitude of the transmission line overshoot (TLO) wave shape. There is a first segment with two traces for connection to the write driver circuitry, an end segment with two traces for connection to the write head and at least two intermediate segments. The number of traces in a segment is different from the number of traces in the segments to which the segment is immediately connected. There is an even number of traces in each segment and the traces in each segment are interleaved. The number of segments and the number of traces in each segment can be selected to achieve the desired impedance levels for the different segments to achieve the desired wave shape for the TLO. All of the traces on the transmission line are preferably coplanar.

Growing community of inventors

San Ramon, CA, United States of America

Rehan Ahmed Zakai