Sony CXA3031Q Datasheet

– 1 –

CXA3031Q

E95318-ST

Read/Write Amplifier (with Built-in Filters) for FDDs

Description

The CXA3031Q is a monolithic IC designed for use with three-mode Floppy Disk Drives, and contains a read circuit (with a four-mode filter system), a write circuit, an erase circuit, and a supply voltage detection circuit, all on a single chip.

Features

• Single 5V power supply

• Filter system can be switched among four modes:

1M, 1.6M/2M, which are each inner track/outer

track

• Filter characteristics can be set to Chebyshev (1dB

ripple) for 1.6M, 2M/inner track only, and to

Butterworth for the other modes

• A custom selection can be made between

Chebyshev (1dB ripple) and Butterworth for the

filter characteristics for 1.6M, 2M/inner track only

• Permits customization of the fc ratio

• Low preamplifier input conversion noise voltage of

2.0nV/√ Hz (typ.) keeps read data output jitter to a

minimum

• Preamplifier voltage gain can be switched between

39dB and 45dB

• In inner track mode (OTF = Low), the voltage gain

is boosted by 3dB, making it possible to minimize

peak shift in inner tracks.

• Time domain filter can be switched between two

modes: 1M, 1.6M/2M

• Write current can be switched among three modes:

1M/1.6M/2M. The inner/outer track current ratio is

fixed for each mode, but can be customized.

• Erase current can be set by an external resistor,

and remains constant. In addition, the current rise

time Tr and fall time Tf are determined according to

the head inductance and current. (Refer to page

20.)

• Damping resistor can be built in. Resistance can be

customized between 2kΩ and 15kΩ in 1kΩ steps.

A damping resistor can not be connected to this IC,

however.

• Supply voltage detection circuit

Applications

Three-mode FDDs

Structure

Bipolar silicon monolithic IC

Absolute Maximum Ratings (Ta = 25°C)

• Supply voltage VCC 7.0 V

• Operating temperature Topr –20 to +75 °C

• Storage temperature Tstg –65 to +150 °C

• Allowable power dissipation

PD 500 mW

• Digital signal input pin Input voltage –0.5 to VCC + 0.3 V

• Power ON output voltage applied VCC + 0.3 V

• Erase output voltage applied VCC + 0.3 V

• Write head voltage applied 15 V

• Write current IW 20 mAo-p

• Erase current IE 30 mA

• Power on output current 7 mA

Operating Conditions

Supply voltage 4.4 to 6.0 V

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.

32 pin QFP (Plastic)

For the availability of this product, please contact the sales office.

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CXA3031Q

Block Diagram and Pin Configuration

XHD

FILTER

MMVA

FCSET

A.GND

HEAD0A

HEAD0B

HEAD1B

HEAD1A

PREOUTA

XWD

RD

XWG

XEG

XS1

XCI

FILTER OUTA

OUTB

XPS

ERA1

ERA0

D.GND

POWER ON

WCLD

WCMD

IESET

XHG

PREOUTB

VCC

NC

OTF

X360

WCHD

WRITE

DRIVER

ERASE

DRIVER

POWER

MONITOR

CONTROL

LOGIC

COMP

TIME

DOMAIN

FILTER

PREAMP

FILTER

DIFF + LPF

(BPF)

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

1

– 3 –

CXA3031Q

Pin Description

Pin No.

Symbol

voltage

Equivalent circuit Description

1

POWER ON

—

Reduced voltage detection output. This is an open collector pin that outputs a low signal when VCC is below the specified value.

VCC

A.GND

100k

1

2 XWD —

Write data input. This pin is a Schmitt-type input that is triggered when the logical voltage goes from High to Low.

VCC

1k

A.GND

2.3V

2

3 RD —

4 XCI —

5 XWG —

6 XEG —

7 XS1 —

8 OTF —

9 XHD —

Read data output. This pin is active when the logical voltage of the write gate signal and the erase gate signal is High.

Write current control. The write current increases when the logical voltage is Low.

Write gate signal input. The write system becomes active when the logical voltage is Low.

Erase gate signal input. The erase system becomes active when the logical voltage is Low.

Head side switching signal input. The HEAD1 system is active when the logical voltage is Low, and the HEAD0 system is active when the logical voltage is High, but only when the logical voltage for the write gate and the erase gate is High.

Filter inner track/outer track mode control. Inner track mode is selected when the logical voltage is Low.

Filter, time domain filter and write current 1M/2M mode control. 2M mode is selected when the logical voltage is Low.

140

V

CC

D.GND

3

VCC

100k

1k

A.GND

2.1V

4 5 6 7 8 9

– 4 –

CXA3031Q

No.

Symbol

voltage

Equivalent circuit Description

18 X360 —

Filter, time domain filter and write current 1M/1.6M mode control. 1.6M mode is selected when the logical voltage is Low.

18 20

VCC

100k

1k

A.GND

2.1V

VCC

A.GND

1.2V 11

1k

147

VCC

A.GND

1.2V

12

140

V

CC

A.GND

300µ

140

300µ

14 15

140

V

CC

A.GND

200µ

140

200µ

17

19

20 XHG

—

Preamplifier voltage gain selection. Gain is boosted by 6dB when the logical voltage is Low compared to when the logical voltage is High.

10 VCC

—

Power supply (5V) connection.

11 FCSET

3.8V

Filter cutoff frequency setting resistor connection. Connect the filter cutoff frequency setting resistor RF between this pin and VCC in order to set the cutoff frequency.

12 MMVA

0.5V

Time domain filter 1st monostable multivibrator pulse width setting. Connect the 1st monostable multivibrator pulse width setting resistor RA between this pin and A.GND.

13 A.GND

—

Analog system GND connection.

14

FILTER OUTB

3.4V

15

FILTER OUTA

3.4V

17

PRE OUTB

3.4V

Filter differential outputs.

19

PRE OUTA

3.4V

Preamplifier differential outputs.

16 (NC) Not connected.

– 5 –

CXA3031Q

Pin No.

Symbol

voltage

Equivalent circuit Description

21 HEAD 1B —

22 HEAD 1A —

23 HEAD 0B —

24 HEAD 0A —

25 WCLD

26 WCMD

27 WCHD

5V when XWG

= High

3.8V when XWG

= Low

28 IESET

29 D.GND

—

30 ERA0

—

31 ERA1

—

Magnetic head input/output connections. Connect the recording/playback magnetic head to these pins, and connect the center tap to VCC. When the logical voltage for Pin 7 (XS1) is Low, the HEAD1 system is active; when the logical voltage is High, the HEAD0 system is active.

1M write current setting resistor connection. Connect the write current setting resistor RWLD between this pin and VCC to set the write current.

1.6M write current setting resistor connection. Connect the write current setting resistor RWMD between this pin and VCC to set the write current.

2M write current setting resistor connection. Connect the write current setting resistor RWHD between this pin and VCC to set the write current.

Erase current setting resistor connection. Connect the erase current setting resistor RE between this pin and VCC to set the erase current.

Digital system GND connection.

Erase current connection for the HEAD0 system.

Erase current connection for the HEAD1 system.

A.GND

21

22

23

24

VCC

A.GND

1.2V

147

25 26 27

VCC

A.GND

1.2V 147

28

VCC

A.GND

30

31

5V

when

XEG

= High

3.8V

when

XEG

= Low

– 6 –

CXA3031Q

No.

Symbol

voltage

Equivalent circuit Description

32 XPS

—

Power saving signal input. When the logical voltage is Low, the IC is in power saving mode. In power saving mode, only the power supply on/off detector operates.

VCC

162k

1k

A.GND

2.1V

32

– 7 –

CXA3031Q

Electrical Characteristics

Current Consumption (Ta = 25°C, VCC = 5V)

Item Symbol Conditions Min. Typ. Max. Unit

Current consumption in read mode

Current consumption in write/erase mode

Current consumption in power saving mode

ICCR

ICCWE

ICCPS

XWG = High XWG = Low,

XEG = Low XPS = Low

—

16

7

—

26

13

0.95

36

19

1.9

mA

Power Supply Monitoring System (Ta = 25°C)

Item Symbol Conditions Min. Typ. Max. Unit

Power supply on/off detector threshold voltage

Power on output saturation voltage

VTH

VSP

VCC = 3.5V I = 1mA

—

3.5—3.9—4.3

0.5

V

Read System (Ta = 25°C, VCC = 5V)

Item Symbol Conditions

Measure-

ment circuit

Measure-

ment Point

Min. Typ. Max. Unit

Preamplifier voltage gain Low gain/outer track

Preamplifier voltage gain Low gain/inner track

Preamplifier voltage gain High gain/outer track

Preamplifier voltage gain High gain/inner track

Preamplifier frequency response

Preamplifier input conversion noise voltage

Preamplifier differential output offset voltage

Filter differential output offset voltage

Filter differential output voltage amplitude

GVLO

GVLI

GVHO

GVHI

BW

EN

VOFSP

VOFSF

VOF

f = 100kHz OTF = High, XHG = High

f = 100kHz OTF = Low, XHG = High

f = 100kHz OTF = High, XHG = Low

f = 100kHz OTF = Low, XHG = Low

GV/GV (100kHz) = –3dB

Band Width = 400Hz to 1MHz, VI = 0

VI = 0

1

D, E

B, C

37.1

40.1

43.1

46.1

5

—

–500

–100

2.8

39.0

42.0

45.0

48.0

—

2.0

—

40.6

43.6

46.6

49.6

—

2.9

+500

+100

—

dB

MHz

nV/√ Hz

mV

Vp-p

Measure-

ment circuit

Measure-

ment Point

Measure-

ment circuit

Measure-

ment Point

– 8 –

CXA3031Q

Read System (Ta = 25°C, VCC = 5V)

Time domain filter monostable multivibrator pulse width

Read data pulse width Read data output low

output voltage Read data output

high output voltage Read data output

∗1

rise time Read data output

∗1

fall time

Peak shift

∗2

T1

T2 VOL

VOH

tr

tf

PS

X360 = X, XHD = High (1M mode)

X360 = Low, XHD = Low (1.6M mode) or X360 = High, XHD = Low (2M mode) Refer to Fig. 1

Refer to Fig. 1 IOL = 2mA

IOH = –0.4mA RL = 2kΩ

CL = 20pF RL = 2kΩ

CL = 20pF VI = 0.25mVp-p to

3.5mVp-p XHG = Low, XHD = Low OTF = Low, X360 = High f = 125kHz, 2M/ inner track mode

Refer to Fig. 1

1

1 1

1

A, F

A A

A

2.25

1.13

260

—

2.8

—

2.5

1.25

400

—

2.75

1.38

540

0.5

—

100

1

µs

ns

V

ns

%

∗1

Read data output: 0.5V to 2.4V

∗2

Signal input level Low gain/outer track: VI = 0.5mVp-p to 10mVp-p Low gain/inner track: VI = 0.5mVp-p to 7mVp-p High gain/outer track: VI = 0.25mVp-p to 5mVp-p High gain/inner track: VI = 0.25mVp-p to 3.5mVp-p

Item Symbol Conditions Min. Typ. Max. Unit

Measure-

ment circuit

Measure-

ment Point