Sony CXA1829N Datasheet

CXA1829N

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8ch. Read/Write Amplifier for Thin Film Heads of Hard Disk Drive

Description

The CXA1829N is a Read/Write amplifier for hard disk drive thin-film heads and is designed to handle up to 8-channel heads.

Features

• Operates on a single 5V power supply.

• Low power consumption.

Read: 115 mW

Write (IW = 15 mA): 160 mW + IW × 5

Power Save: 7 mW

• Write current can be varied through an external

resistor. Built-in stabilizer circuit provides stable

current, preventing voltage and temperature drift.

• Drives up to 8 heads.

• Supports thin film heads or 2-pin MIG heads.

• Emitter follower-type Read amplifier features 290

times gain (typ.).

• Write-unsafe detection circuit.

• Damping resistance is switched at Write (315 Ω).

• Simultaneous Write function.

• Supply voltage monitor circuit prohibits error

writing during power surge or abnormal voltage.

• IC protection circuit for head-to-ground short circuit

protection.

• Differential input capacitance at Read: 14 pF (typ.).

• Write data input minimum pulse width: 10 ns

• Read data output in Write mode becomes a high

impedance due to the improved Read data offset

when Write is switched to Read.

• Non-selected head DC voltage falls to GND level.

Absolute Maximum Ratings (Ta=25°C)

• Supply voltage VCC 7.0 V

• Write current IW 20 mAo-p

• Operating temperature Topr –20 to +75 °C

• Operating temperature at Simultaneous Write

• Storage temperature Tstg –55 to +150 °C

• Allowable power dissipation

Recommended Operating Conditions

• Supply voltage VCC 5V±10% V

30 pin SSOP (Plastic)

Topr –20 to +30 °C

PD 480 mW

Structure

Bipolar silicon monolithic IC

Sony reserves the right to change products and specifications without prior notice. This information does not convey any license by any implication or otherwise under any patents or other right. Application circuits shown, if any, are typical examples illustrating the operation of the devices. Sony cannot assume responsibility for any problems arising out of the use of these circuits.

—1—

E94433A49-TE

Block Diagram and Pin Configuration

CXA1829N

GND

H0X

H0Y

H1X

H1Y

H2X

H2Y

H3X

H3Y

30

29

28

27

26

GND

PS

R/W

WC

RDY

1

2

3

4

5

AMP

DRIVER

MODE

CONTROL

WRITE CURRENT SOURCE

AMP

6

7

DRIVER

AMP

25

24

RDX

HS0

HEAD

23

8

DRIVER

HS1

SELECT

9

AMP

22

HS2

POWER

DRIVER

ON/OFF DETECTOR

T - FF

WRITE UNSAFE DETECTOR

WRITE SERVO

AMP

10

H4X

11

H4Y

12

H5X

13

H5Y

14

H6X

15 16

H6Y

AMP

DRIVER

IC PROTECTOR

21

20

19

18

17

V

CC

WDI

WUS

WSER

H7X

H7Y

—2—

Pin Description

No. Symbol Equivalent circuit Description

CXA1829N

1, 30 GND

2, 3 H0X, H0Y 4, 5 H1X, H1Y 6, 7 H2X, H2Y

8, 9 H3X, H3Y 10, 11 H4X, H4Y 12, 13 H5X, H5Y 14, 15 H6X, H6Y 16, 17 H7X, H7Y

19 WUS

20 WDI

GND connection. Head input.

VCC

10

2

12

4

14

6

16

8 3

11

5

13

7

15

9

17

2k 2k

200k

330

GND

VCC

8 channels provided.

Write-unsafe detection output. Open collector output. When it is high in Write mode, an error is

19

GND

VCC

detected.

Write data input. When high changes to low, input is triggered.

21 VCC 22 HS2 23 HS1 24 HS0

28 R/W

29 PS

20

22 23 24

28 29

100k

2.1V

1.4V

2.1V

GND

2.1V

VCC

GND

VCC

GND

5 V power supply. Head select signal input. Eight heads are selected as shown in Table 2.

Read/Write signal input. Read at high; Write at low.

Power save signal input. Power save at high.

—3—

No. Symbol Equivalent circuit Description

CXA1829N

18 WSER

25 RDX 26 RDY

27 WC

18

25

26

100k

2.1V

VCC

GND

VCC

GND

CC

V

Simultaneous Write signal input. Set to low for simultaneous Write mode.

Read amplifier output. Becomes a high impedance at Write.

A setting resistor for the Write current value is connected between this pin and GND.

27

1.25V GND

—4—

CXA1829N

Electrical Characteristics (unless otherwise specified, VCC = 5 V, Ta = 25°C, Write current IW = 15 mA)

Refer to Measurement Circuit 1.

Item Symbol Measurement conditions ment Min. Typ. Max. Unit

Current consumption for Read Current consumption for Write Current consumption for Servo Current consumption for Power save

I

IW

ISE

IP

R

R/W="H"

R/W="L"

WSER="L"

PS="H"

Measure-

point

E172333

E

24 32 45

W +IW +IW

+I

71 91 111

W +4×IW +4×IW

+4×I

E 0.8 1.4 2.0

mA

Digital low input voltage

Digital high input voltage

Digital low input current

Digital high input current

Write-unsafe output saturation voltage Write-unsafe output leak current Power ON/OFF detector threshold voltage Write current setting range

Write current accuracy

Read amplifier differential voltage gain

VIL

VIH

IL

IH

VWUS

IWUS

VTH

IW

∆Iw

AV

High applied voltage: 5 V Low applied voltage: 0 V

Output current: 1 mA

Current flowing between head pins.

When Write current is I

K

___

W=

Rw

(Rw:Ω),

I

W [mA], then:

Refer to Fig. 12 (Characteristics) for K. Input voltage SG1:1mVp-p,300kHz Load resistance (RDX, RDY): 1kΩ

B 0.8 DV F 2.0 G H -70

IµA J70

C 0.5 V

C10µA

CC

V

3.6 3.9 4.3 V

A A 5 15 mAo-p

A-8 8%

K 245 290 335 V/V

Bandwidth (-3 dB)

Input conversion noise voltage Common mode rejection ratio

BW

EN

CMRR

Frequency at which Av drops by 3dB

Head impedance: 0 Ω

In-phase input voltage SG2:100mVp-p, 10 MHz

—5—

K 60 MHz

K 0.55 0.7

nV

√Hz

K5077 dB