Sony CXA3071N Datasheet

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CXA3071N

E96146B8Z

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

Description

The CXA3071N 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

• All filter, write current and other characteristics can

be set with a single external resistor.

• 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 and a custom

selection can be made between Chebyshev (1dB

ripple) and Butterworth for 1.6M, 2M/inner track

only.

• 1M/outer track f0 and the fc ratio for each mode

can be customized.

• Preamplifier voltage gain can be set to 45dB or

48dB by switching the filter mode and inner/outer

track.

• Preamplifier and filter output are monitored with

the same pins. These pins are normally set to filter

output, but the preamplifier output can be

monitored by temporarily setting the SETR pin (Pin

20) to Low.

• Time domain filter can be switched between two

modes: 1M, 1.6M/2M.

In addition, the pulse width can be customized.

• Write current can be switched among six modes

according to the mode and inner/outer track

setting.

The current value can be customized for each

mode.

• Erase current remains constant, and the current

value can be customized.

• Damping resistor can be built in. Resistor can be

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

• 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

• Digital signal input pin voltage

–0.5 to VCC + 0.3 V

• Power ON output applied voltage VCC + 0.3 V

• Erase output applied voltage VCC + 0.3 V

• Write head applied voltage 15 V

• Power ON output current 7 mA

• Operating temperature Topr –20 to +75 °C

• Storage temperature Tstg –65 to +150 °C

• Allowable power dissipation

PD 375 mW

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.

20 pin SSOP (Plastic)

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

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CXA3071N

Block Diagram and Pin Configuration

WRITE

DRIVER

COMP

PREAMP

CONTROL

LOGIC

TIME

DOMAIN

FILTER

DIFF + LPF

(BPF)

POWER

MONITOR

ERASE

DRIVER

2

3

4

5

6

7

8

9

10

1

11

12

13

14

15

16

17

18

19

20

HEAD1A

HEAD1B

HEAD0A

HEAD0B

GND

ERA0

ERA1

PONOUT

MONITORA

MONITORB

SETR

V

CC

X360

XHD

OTF

XS1

XEG

WG

RD

XWD

– 3 –

CXA3071N

Pin Description

Pin No.

Symbol

Pin voltage

Equivalent circuit Description

1

2

3

4

HEAD1A

HEAD1B

HEAD0A

HEAD0B

—

Magnetic head inputs/outputs. Connect the recording/playback magnetic head to these pins, and connect the center tap to V

CC. When the logical voltage for

Pin 15 (XS1) is Low, the HEAD1 system is active; when the logical voltage is High, the HEAD0 system is active.

GND

2

3

4

1

5

GND —

GND connection.

6 ERA0

—

7

ERA1

—

8

9

10

PON OUT

—

MONITORA

4.0V during filter output

3.4V during preamplifier output

4.0V during filter output

3.4V during preamplifier output

MONITORB

Erase output for the HEAD0 system.

Erase output for the HEAD1 system.

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

MONITOR differential outputs. These pins are set to filter output during normal read mode, but the preamplifier output can be monitored by temporarily setting Pin 20 (SETR) to Low.

VCC

GND

6 7

VCC

GND

8

100k 100k

500µ500µ

9

10

V

CC

GND

– 4 –

CXA3071N

11 XWD —

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

VCC

1k

GND

2.3V

11

140

V

CC

GND

12

GND

0.65 V

CC

0.35 VCC

13

147

VCC

0.5 VCC

VCC

100k

1k

GND

2.1V

14 15 16

17 18

12

13RDWG

—

0.5VCC during read

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

WG signal input. The write system becomes active when the logical voltage is High. The IC is in power saving mode when the logical voltage is Low. The read system becomes active when the logical voltage is Z.

14

XEG

—

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

15

XS1

—

16

OTF

—

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 WG signal is Z and of the XEG signal is High.

Filter inner track/outer track mode control. Outer track mode is selected when the logical voltage is High.

Filter, time domain filter and write current 1M/2M mode control. 1.6M/2M mode is selected when the logical voltage is Low.

17

18

19

XHD

X360

VCC

—

Filter, time domain filter and write current

1.6M/2M mode control. 1.6M mode is selected when the logical voltage is Low.

Power supply (5V) connection.

Pin No.

Symbol

Pin voltage

Equivalent circuit Description

– 5 –

CXA3071N

3.8V

20 SETR

Filter cutoff frequency, time domain filter 1st monostable multivibrator pulse width, read data, write current and erase current setting resistor connection. Connect the setting resistor R between this pin and VCC.

Pin No.

Symbol

Pin voltage

Equivalent circuit Description

147

VCC

20

1.2V

GND

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CXA3071N

Electrical Characteristics

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

Current consumption in read mode

Current consumption in write/erase mode

Current consumption in power saving mode

ICCR

ICCWE

ICCPS

WG = "Z"

WG = "H", XEG = "L"

WG = "L"

—

15.0

11.0

—

25.0

17.0

1.2

35.0

23.0

2.0

mA

Power Supply Monitoring System (Ta = 25°C)

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

0.5VV

Read System (Ta = 25°C, VCC = 5V)

Preamplifier voltage gain 1M/outer track

Preamplifier voltage gain 1M/inner track

Preamplifier voltage gain

1.6M, 2M/ outer track

Preamplifier voltage gain

1.6M, 2M/ inner track

Preamplifier frequency response

Preamplifier input conversion noise voltage

GVLO

GVLI

GVHO

GVHI

BWO

ENO

f = 100kHz, OTF = "H", XHD = "H", X360 = "X"

f = 100kHz, OTF = "L", XHD = "H", X360 = "X"

f = 100kHz, OTF = "H", XHD = "L", X360 = "X"

f = 100kHz, OTF = "L", XHD = "L", X360 = "X"

GV/GV0 = –3dB

BW = 400Hz to 1MHz, VI = 0

1

A, B

43.1

46.1

43.1

46.1

5

—

45.0

48.0

45.0

48.0

—

2.0

46.6

49.6

46.6

49.6

—

2.9

dB

MHz

nV/√Hz

Item Symbol

Conditions

Measurement circuit

Measurement point

Min. Typ. Max. Unit

Item Symbol

Conditions

Measurement circuit

Measurement point

Min. Typ. Max. Unit

Item Symbol

Conditions

Measurement circuit

Measurement point

Min. Typ. Max. Unit

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CXA3071N

Read System (Ta = 25°C, VCC = 5V)

Filter output voltage amplitude

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

VOF

T1

T2

VOL

VOH

tr

tf

PS

X360 = "X", XHD = "H" (1M mode)

X360 = "X", XHD = "L" (1.6M/2M mode)

IOL = 2mA

IOH = –0.4mA RL = 2kΩ

CL = 20pF RL = 2kΩ

CL = 20pF VI = 0.25mVp-p to

3.5mVp-p X360 = "H", XHD = "L" OTF = "L" f = 125kHz, 2M/inner track mode

1

A, B

C, D

D

1.4

2.25

1.16

300

—

2.8

—

2.50

1.29

400

—

2.75

1.42

500

0.5

—

100

1

Vp-p

µs

ns

V

ns

%

∗1

Read data output: 0.5V to 2.4V

∗2

Signal input level

1M, 1.6M, 2M/outer track: VI = 0.25mVp-p to 5mVp-p 1M, 1.6M, 2M/inner track: VI = 0.25mVp-p to 3.5mVp-p

Item Symbol Conditions

Measurement circuit

Measurement point

Min. Typ. Max. Unit

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CXA3071N

Fig. 1. 1st and 2nd monostable multivibrator pulse width precision

and peak shift measurement conditions

• 1st monostable multivibrator pulse width precision

When X360 = "X" and XHD = "H":

ETM1 = ( –1) × 100 [%]

When X360 = "X" and XHD = "L":

ETM1' = ( –1) × 100 [%]

• 2nd monostable multivibrator pulse width = T2

• Peak shift

PS = × 100 [%]

T1

2.5µs

12TA – TB

TA + TB

T1

1.29µs

External Comparator Output

(Measurement point C)

T1 T2

TA TB

1.4V

Read data output

(Measurement point D)