International Business Machines Corporation

Hitachi Global Storage Technologies Netherlands B.v.

Klaas Berend Klaassen

John Thomas Contreras

Stephen A Jove

Jacobus C Van Peppen

Jacobus Cornelis Leonardus Van Peppen

Calvin Shizuo Nomura

Gordon James Smith

David A Thompson

Christopher H Bajorek

Paul Wingshing Chung

Thomas W Glaser

Charles R Nielsen

George R Santana

Satya Prakash Arya

Nobumasa Nishiyama

Michael L Workman

Jacobus C Leonardus Van Peppen

Jacobus C VanPeppen

Robert Fontana

Vladimir Nikitin

David John Seagle

Bruce Alvin Gurney

Richard Hsiao

Stefan Maat

A David Erpelding

Howard Gordon Zolla

Raymond Alan Richetta

Satoru Araki

Michael O Jenkins

Michael Paul Salo

Hung Liang Hu

Robert Andrew Kertis

Liesl Folks

Samuel Wei-san Yuan

Timothy J Moran

Richard James Reay

Walter Eugene Weresin

Paik Saber

Jaydip Bhaumik

Long Tran

Byron R Brown

John Thomas Conteras

Jacobus C Leonandus Van Peppen

Ramona Marie Patterson

Joseph J Lum

Edward Hing Pong Lee

Chon N Vo

Jacobus C L Van Peppen

A method for manufacturing a hard disk drive is described. The method includes providing a motor assembly, the motor assembly comprising a stationary portion and a rotatable portion for rotating a magnetic disk with respect to said stationary portion and providing a base for receiving the motor assembly. The method further includes providing an adhesive for mounting the motor assembly to said base wherein the adhesive is electrically conductive and mounting the stationary portion of the motor assembly to the base utilizing the adhesive such that the adhesive provides a low resistance path between the base and the motor assembly.

Motor mount for interference suppression in a hard disk drive

Magnetic sensing chips and methods of fabricating the magnetic sensing chips are disclosed. A magnetic sensing chip as described herein includes an EMR sensor formed on a substrate from multiple semiconductor layers. One or more of the semiconductor layers form a quantum well comprising a two-dimensional electron gas (2DEG) or hole gas (2DHG). The magnetic sensing chip also includes one or more transistors formed on the substrate from the multiple semiconductor layers. The transistor(s) likewise include a quantum well comprising a 2DEG or 2DHG. The EMR sensor and the transistor(s) are connected by one or more connections so that the transistor(s) amplifies data signals from the EMR sensor.

EMR sensor and transistor formed on the same substrate

Embodiments of the present invention provide a mixed-mode amplifier for amplifying signals in data storage devices such as disk drives. In one embodiments, a circuit for amplifying data signals comprises a magnetoresistive sensor having a bias voltage applied thereto; a signal amplifier which amplifies a signal detected by the magnetoresistive sensor having the bias voltage applied thereto; a feedback control block which is coupled to an output of the signal amplifier and outputs a feedback current used to vary a loop gain of the circuit; a bias setting circuit which outputs a bias setting current; and a transimpedance amplifier which receives the bias setting current from the bias setting block and the feedback current from the feedback control block and generates the bias voltage applied to the magnetoresistive sensor.

Direct coupled wide-bandwidth front-end with smart bias control amplifier

Circuits and methods are provided for write through drivers in disk drive systems. A write through driver is a transceiver that includes a write driver circuit and a receiver circuit. The write driver drives a current signal to a write element through a first conductive interconnect. The write element writes data patterns to a magnetic hard disk in response to the current signal from the write driver circuit. The current signal returns to the receiver circuit through a second conductive interconnect. The return signal can be used for the diagnosis of write-safe conditions.

Write through drivers for disk drive systems

A current-perpendicular-to-the-plane (CPP) magnetoresistive (MR) read head structure has the MR read head located between first and second shields (S, S) on a substrate with a shunt resistor Rconnecting Sto the substrate and a shunt resistor Rconnecting Sto the substrate, with Rand Rbeing approximately equal. Because Rand Rare close enough in value there is no significant interference pickup in the low frequency region. The shunt resistors can be formed from high-resistivity metal nitrides or cermets. The spacing between the substrate and Smay be selected to make the capacitance between Sand the substrate approximately equal to the capacitance between Sand the substrate to substantially reduce interference pickup in the high frequency region. Equalization conductors (EC, EC) may be connected to the substrate and spaced from Sand S, respectively, by electrically insulating material to create additional capacitances with values selected to substantially equalize the total parasitic capacitance on Swith the total parasitic capacitance on S

Current-perpendicular-to-the-plane (CPP) magnetoresistive sensor with impedance adjustment

An electrical lead suspension (ELS) having partitioned air slots. The ELS includes a laminate. A first plurality of signal traces and a second plurality of traces are in a first formed layer of the laminate. The second plurality of traces may be signal traces or power traces. The laminate has a dielectric layer between the first formed layer and a second formed layer. A plurality of partitioned air slots is in the second formed layer of the laminate. The portion of the ELS having a plurality of partitioned air slots supporting the at least the first plurality of signal traces and the portion of the ELS having a second plurality of partitioned air slots or patterns supporting the second plurality of traces. The supporting of the first plurality of signal traces separate from the second plurality of traces reduces write-to-read cross talk and signal loss. Offsetting the first plurality of air slots from second plurality of air slots further reduces cross talk and signal loss and restores some of the structural rigidity lost due to in line (e.g., aligned) slots.

Electrical lead suspension having partitioned air slots

A method and apparatus for reducing crosstalk and signal loss in an electrical interconnect is disclosed. The electrical interconnect includes a laminate. A plurality of signal traces and a subsequent plurality of traces are in a first formed layer of the laminate. The subsequent plurality of traces may be signal traces or power traces. The laminate has a dielectric layer between the first formed layer and a second formed layer. A plurality of serpentine patterns are in the second formed layer of the laminate. The plurality of serpentine patterns is separated from subsequent patterns. The plurality of serpentine patterns supports the plurality of signal traces and the subsequent plurality of patterns supports the subsequent plurality of traces. The supporting of the plurality of signal traces separate from the subsequent plurality of traces reduces write-to-read crosstalk and signal loss.

Method and apparatus for reducing crosstalk and signal loss in flexing interconnects of an electrical lead suspension

In one illustrative example disclosed, a magnetic storage device includes at least one magnetic disk; a magnetic head which includes first and second read sensors; a suspension which supports the magnetic head relative to the magnetic disk; and read circuitry which includes a preamplifier. The preamplifier has a first input port coupled to the first read sensor; a second input port coupled to the second read sensor; a first bias source coupled to the first input port for actively current/voltage biasing the first read sensor; a second bias source coupled to the second input port for zero biasing the second read sensor; and a subtractor having first and second inputs coupled to the first and the second input ports, respectively. The first input of the subtractor is provided with a first signal which includes a read sensor data signal and an interference signal, whereas the second input of the subtractor is provided with a second signal which includes the interference signal but not the read sensor data signal. Thus, an output of the subtractor provides a read sensor signal without the interference signal.

Preamplifier circuit with signal interference cancellation suitable for use in magnetic storage devices

An example of a multi-layer structure which may be used for supporting a transducer includes a support layer and an etch stop layer formed from a refractory metal on the support layer. A first electrically conducting layer of copper may be positioned on the etch stop layer. A dielectric layer may be provided on the first electrically conducting layer. A second electrically conducting layer of copper may be provided on the dielectric layer. The dielectric layer is positioned between the first electrically conducting layer and the second electrically conducting layer. The second electrically conducting layer may include a plurality of separate electrically conducting lines.

Integrated lead suspension for use in a disk drive using a tri-metal laminate and method for fabrication

The spacing decrease between pole tips of a write element and a magnetic medium that is associated with the write element is linearly proportional to an input signal, such as an input voltage or current, to a slider flying height controller for a hard disk drive. The flying height controller includes a heater current controller and a multiplexer. The heater current controller receives the input signal and outputs a control current proportional to the input signal. The multiplexer couples the control current to a heating element associated with the write element on a selected slider body during a read operation. The heating element dissipates a power that is proportional to the control current and causes a decrease in the spacing between the pole tips of the write element and the magnetic medium that is linearly proportional to the control current and to the input signal.

Circuitry for linear control of head flying height using thermal means

A magnetic transducer including an electrically conductive shield (ECS) which is disposed between the substrate and first magnetic shield is described. The ECS is preferably embedded in an insulating undercoat layer. The ECS is preferably electrically isolated from the magnetic sensor element and is externally connected to a ground available in the disk drive through the arm electronics. Two alternative ways for connecting the ECS to a ground are described. In one embodiment which is only effective with single-ended input type arm electronics, the ECS is connected to a ground through a via to a lead pad for the read head which is connected to the ground of the arm electronics. In a second and more preferred embodiment a separate lead pad is included on the head to allow the ECS to be connected to electronic or case ground when the head is installed in the arm. The extent of the ECS should be sufficiently large to cover the read head portion of the transducer, i.e., from the edge of the first magnetic shield to the outer edges of the read contact pads, but should preferably not cover the write head pads.

Magnetic transducer with electrically conductive shield for reducing electromagnetic interference

A method (and magnetic recording circuit structure) for write drivers to reduce the reversal time for the current through the inductive recording head, includes a write driver output stage providing a write signal output with a write signal source strength S , a magnetic write head with a write signal input essentially equal to strength S , and an interconnect circuit having a characteristic impedance Z coupled to the write signal output of the write driver output stage and the magnetic write head. The write driver output stage preferably includes a source-side termination circuit having output impedance Z , wherein the source-side termination circuit output impedance Z is substantially equal to Z and the source strength S of the write driver at the input of the interconnect circuit is temporarily enlarged after every polarity reversal of the write signal for a predetermined time duration &Dgr;t.

Characteristically terminated write driver with compensation for magnetic response and method therefor

A portable computer includes a battery and a connection to an external power source, a two-speed data storage device being supplied power from one or more of the battery and the external power source, and a controller attached to the storage device. With the invention, when the storage device is powered by the internal battery, the controller not only reduces the rotation speed and the clock rate of the storage device, but also reduces the power consumption of the read/write electronics module inside the disk drive by lowering the power supply voltage for the write driver inside said module and lowering the tail currents for the amplifier stages in the readback amplifier inside said module. When the storage device is powered by an external power source, the controller will run the storage device at full speed and highest clock rate, and will provide the write driver inside the read/write electronics module with a power supply voltage high enough to accommodate the resulting higher data rate, and will provide tail currents in the amplifier stages of the readback amplifier high enough to accommodate the higher required bandwidth for the readback amplifier.

Data storage device having selectable performance modes for use in dual powered portable devices

An interconnect circuit for a readout channel front-end for a disk drive is disclosed that includes a forward line and a return line. Both the forward line and the return line have a first end and a second end. The first end of both the forward line and the return line is connectable to a magnetoresistive head. The second end of both the forward line and the return line is connectable to a single-ended preamplifier. The return line is arranged to be disposed between the forward line and a suspension for a magnetoresistive head. The forward trace has a first predetermined width and the return trace has a second predetermined width that can be the same or different from the first predetermined width. When the interconnect circuit is in a disk drive, the first end of the forward line is connected to a magnetoresistive head, and the second end of the forward line is connected to a single-ended preamplifier. Similarly, the first end of the return line is connected to the magnetoresistive head, and the second end of the return line is connected to the single-ended preamplifier. The return line is disposed between the forward line and a suspension for the magnetoresistive head. The characteristic impedance of the interconnect circuit is selected to be about equal to an input resistance of the single-ended preamplifier. Accordingly, the high-frequency roll-off of a transfer characteristic of the interconnect circuit is primarily determined by a high-frequency skin-effect loss in each of the forward and return lines, and the transfer characteristic of the interconnect circuit does not exhibit a &frac14; wavelength effect notch.

Integrated trace suspension interconnect for high-data-rate single-ended preamplifier for (G)MR elements

A method and system for providing a current-sensing preamplifier for use with a magnetoresistive sensor is disclosed. The method includes providing at least one input device coupled with the magnetoresistive sensor, providing a gain stage, and providing a feedback circuit. In a system aspect, the current-sensing preamplifier includes at least one input device. The at least one input device is coupled with the magnetoresistive sensor through an interconnect having a characteristic impedance. The at least one input device provides an input impedance for the current-sensing preamplifier. The current-sensing preamplifier also includes a gain stage coupled with the at least one input device and a feedback circuit coupled with the gain stage and the at least one input device. The feedback circuit provides at least one signal to the at least one input device. The at least one signal controls the input impedance based on at least one error signal.

Quasi-current sensing input impedance controlled preamplifier for magnetoresistive elements

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San Jose, CA, United States of America

Klaas Berend Klaassen