# US 9,159,344 B2 · Disk drive read circuit comprising an AC coupled sense amplifier for amplifying a read signal

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 9,159,344 B2
- Document ID: US9159344B2
- Status: Granted
- Kind: B2
- Application number: 13/890,131
- Filed: 2013-05-08
- Published: 2014-11-13
- Granted: 2015-10-13
- Earliest claimed: 2013-05-08
- Assignees: Western Digital Technologies, Inc.
- Applicants: Western Digital Technologies, Inc.
- Inventors: Michael L. Mallary; Yiao-Tee Hsia; William D. Huber
- Web page: https://patentgrep.com/patent/US9159344B2

## CPC

- G11B 5/4853: {Constructional details of the electrical connection between head and arm}
- G11B 5/4826: {Mounting, aligning or attachment of the transducer head relative to the arm assembly, e.g. slider holding members, gimbals, adhesive (G11B5/484 takes precedence; details of head housings or structures G11B5/10, G11B5/127; adjustment relative to the record carrier G11B5/56)}
- G11B 5/40: Protective measures on heads, e.g. against excessive temperature (G11B5/31 takes precedence; protection against wear G11B5/255 {; protective structure of the head: see under structures, e.g. G11B5/3106})
- G11B 2020/0005: {DTS audio codecs}
- Y10T 29/4913: Assembling to base an electrical component, e.g., capacitor, etc.
- G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A disk drive read circuit is disclosed comprising a read element for generating a read signal, and a sense amplifier comprising an input terminal coupled through a first capacitor to the read element and an output terminal coupled through a second capacitor to a transmission line, wherein the sense amplifier is for amplifying the read signal.

## Claims

### Claim 1

A disk drive read circuit comprising:
a read element for generating a read signal; and
a sense amplifier comprising an input terminal coupled through a first capacitor to the read element and an output terminal coupled through a second capacitor to a first end of a transmission line, wherein:
a second end of the transmission line is coupled to a preamplifier; and
the sense amplifier is for amplifying the read signal,
wherein the transmission line provides at least one of a bias signal to the read element and power to the sense amplifier.

### Claim 2 (depends on 1)

The disk drive read circuit as recited in claim 1, wherein the input terminal of the sense amplifier is coupled through the first capacitor to the read element proximate the read element.

### Claim 3 (depends on 2)

The disk drive read circuit as recited in claim 2, wherein the input terminal of the sense amplifier is coupled through the first capacitor to the read element by a distance of not more than 2 millimeters.

### Claim 4 (depends on 2)

The disk drive read circuit as recited in claim 2, wherein the input terminal of the sense amplifier is coupled through the first capacitor to the read element by a distance of not more than 4 millimeters.

### Claim 5 (depends on 1)

The disk drive read circuit as recited in claim 1, wherein the second end of the transmission line is coupled to a bond pad of a slider, and the bond pad of the slider is coupled to a flex circuit.

### Claim 6 (depends on 5)

The disk drive read circuit as recited in claim 5, wherein the sense amplifier comprises at least one transistor and at least one resistor.

### Claim 7 (depends on 6)

The disk drive read circuit as recited in claim 6, wherein:
the read element is fabricated on a substrate of a first wafer; and
at least the resistor of the sense amplifier is fabricated on the substrate of the first wafer.

### Claim 8 (depends on 1)

The disk drive read circuit as recited in claim 1, wherein:
the read element is fabricated on a substrate of a first wafer; and
at least one of the first and second capacitors is fabricated on the substrate of the first wafer.

### Claim 9 (depends on 1)

The disk drive read circuit as recited in claim 1, wherein:
the sense amplifier is coupled to a slider through a first flex circuit, wherein the slider comprises the read element; and
the sense amplifier is coupled to a preamplifier through a second flex circuit.

### Claim 10 (depends on 1)

The disk drive read circuit as recited in claim 1, wherein the sense amplifier comprises an emitter follower.

### Claim 11 (depends on 1)

The disk drive read circuit as recited in claim 1, wherein the sense amplifier comprises a differential amplifier.

### Claim 12 (depends on 11)

The disk drive read circuit as recited in claim 11, wherein a voltage gain of the differential amplifier is greater than one.

### Claim 13

A method of manufacturing a disk drive read circuit comprising a read element for generating a read signal, the method comprising:
coupling an input terminal of a sense amplifier through a first capacitor to the read element; and
coupling an output terminal of the sense amplifier through a second capacitor to a first end of a transmission line, wherein:
a second end of the transmission line is coupled to a preamplifier; and
the sense amplifier is for amplifying the read signal,
wherein the transmission line provides at least one of a bias signal to the read element and power to the sense amplifier.

### Claim 14 (depends on 13)

The method as recited in claim 13, wherein the input terminal of the sense amplifier is coupled through the first capacitor to the read element proximate the read element.

### Claim 15 (depends on 14)

The method as recited in claim 14, wherein the input terminal of the sense amplifier is coupled through the first capacitor to the read element by a distance of not more than 2 millimeters.

### Claim 16 (depends on 14)

The method as recited in claim 14, wherein the input terminal of the sense amplifier is coupled through the first capacitor to the read element by a distance of not more than 4 millimeters.

### Claim 17 (depends on 13)

The method as recited in claim 13, wherein the second end of the transmission line is coupled to a bond pad of a slider, and the bond pad of the slider is coupled to a flex circuit.

### Claim 18 (depends on 17)

The method as recited in claim 17, wherein the sense amplifier comprises at least one transistor and at least one resistor.

### Claim 19 (depends on 18)

The method as recited in claim 18, further comprising:
fabricating the read element on a substrate of a first wafer; and
coupling the sense amplifier to the read element prior to slicing the first wafer.

### Claim 20 (depends on 19)

The method as recited in claim 19, further comprising:
fabricating at least the transistor of the sense amplifier on a substrate of a second wafer; and
bonding the transistor to the first wafer prior to slicing the first wafer.

### Claim 21 (depends on 18)

The method as recited in claim 18, further comprising:
fabricating the read element on a substrate of a first wafer; and
fabricating at least the resistor of the sense amplifier on the substrate of the first wafer.

### Claim 22 (depends on 18)

The method as recited in claim 18, further comprising:
fabricating the read element on a substrate of a first wafer; and
fabricating at least one of the first and second capacitors on the substrate of the first wafer.

### Claim 23 (depends on 13)

The method as recited in claim 13, further comprising:
coupling a slider comprising the read element to the sense amplifier through a first flex circuit; and
coupling the sense amplifier to a preamplifier through a second flex circuit.

### Claim 24 (depends on 13)

The method as recited in claim 13, wherein the sense amplifier comprises an emitter follower.

### Claim 25 (depends on 17)

The method as recited in claim 17, wherein the sense amplifier comprises a differential amplifier.

### Claim 26 (depends on 25)

The method as recited in claim 25, wherein a voltage gain of the differential amplifier is greater than one.

### Claim 27

A disk drive read circuit comprising:
a read element for generating a read signal; and
a sense amplifier comprising an input terminal coupled through a first capacitor to the read element and an output terminal coupled through a second capacitor to a first end of a transmission line, wherein:
a second end of the transmission line is coupled to a preamplifier;
the sense amplifier is for amplifying the read signal; and
the second end of the transmission line is coupled to a bond pad of a slider, and the bond pad of the slider is coupled to a flex circuit.

### Claim 28

A disk drive read circuit comprising:
a read element for generating a read signal; and
a sense amplifier comprising an input terminal coupled through a first capacitor to the read element and an output terminal coupled through a second capacitor to a first end of a transmission line, wherein:
a second end of the transmission line is coupled to a preamplifier;
the sense amplifier is for amplifying the read signal;
the sense amplifier is coupled to a slider through a first flex circuit, wherein the slider comprises the read element; and
the sense amplifier is coupled to a preamplifier through a second flex circuit.

### Claim 29

A method of manufacturing a disk drive read circuit comprising a read element for generating a read signal, the method comprising:
coupling an input terminal of a sense amplifier through a first capacitor to the read element; and
coupling an output terminal of the sense amplifier through a second capacitor to a first end of a transmission line, wherein:
a second end of the transmission line is coupled to a preamplifier;
the sense amplifier is for amplifying the read signal; and
the second end of the transmission line is coupled to a bond pad of a slider, and the bond pad of the slider is coupled to a flex circuit.

### Claim 30

A method of manufacturing a disk drive read circuit comprising a read element for generating a read signal, the method comprising:
coupling an input terminal of a sense amplifier through a first capacitor to the read element; and
coupling an output terminal of the sense amplifier through a second capacitor to a first end of a transmission line, wherein:
a second end of the transmission line is coupled to a preamplifier; and
the sense amplifier is for amplifying the read signal,
coupling a slider comprising the read element to the sense amplifier through a first flex circuit; and
coupling the sense amplifier to a preamplifier through a second flex circuit.