ROHM BH7272KV Datasheet

1

Video ICs

Two-channel VCR PRE / REC amplifier for Digital VCRs

BH7272KV

The BH7272KV is a head amplifier developed for use in digital video cassette recorders. Both PB and REC have excellent frequency characteristics making this IC an ideal choice for digital recording and playback. The small VQFP48 package facilitates compact design of portable equipment such as video cameras.

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Applications

Digital video cassette recorders

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Features

1) The playback amplifier is a differential amplifier with an overall gain of 54dB (Typ.), and has low-noise transistors as the first stage. The feedback circuit is not included, so provide negative feedback for head peak damping, and positive feedback to cancel the input capacitance using external components.

2) The playback AGC amplifier has ± 10dB of control range.

3) The recording current amplifier is a BLT current amplifier. Use external components to construct the head peak damping circuit.

4) Recording limit amplifier is included. Recording AGC amplifier not included.

5) The signal system V

CC is 4.9V, and the control sys-

tem V

CC is 3.0V.

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Absolute maximum ratings (Ta = 25°C)

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Recommended operating conditions (Ta = 25°C)

Parameter Symbol Limits Unit Applied voltage Power dissipation Operating temperature Storage temperature

V

CC

Pd Topr Tstg

7.0

– 20 ~ + 65 – 55 ~ + 125

V

mW

°C °C

∗

When mounted on a 70mm × 70mm × 1.6mm glass epoxy board.

∗

Reduced by 9.0mW for each increase in Ta of 1°C over 25° .

∗

900

Parameter

Symbol Min. Typ. Max. Unit Conditions Signal system Control system

V

CC 5V

V

CC 3V

4.6

2.8

4.9

3.0

5.2

3.2

VV14, 19, 38, 47pin

16pin

䊊Not designed for radiation resistance.

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Video ICs BH7272KV

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Block diagram

36 35 34 33 32 31 30 29 28 27 26 25

24

23

22

21

20

19

18

17

16

15

14

13

12

1110987654321

48

47

46

45

44

43

42

41

40

39

38

37

1k

10k

3rd

2nd

AGC

DET

IAMP

PRE

IAMPIAMP

PRE

IAMP

1k

10k

Bias

BH7272KV

LIMIT

LIMIT LEVEL adj

LIMIT Vth adj

REC LIMIT – OUT

REC LIMIT + OUT

GND

Vcc 4.9V

REC GATE

REC “H”

Vcc 3.0V

BIAS FILTER

Vcc 4.9V

REC BTL B I0adj

GND

Vcc 4.9V

PB 2nd OUT A

PB 2nd OUT B

PB 2nd IN A

PB 2nd IN B

PB SW – OUT

PB SW + OUT

HEAD SW CTRL

PB “H”

Vcc 4.9V

REC BTL A I0adj

PB SW B OUT

PB SW A OUT

N.C.

PB MUTE

AGC DET GATE

PB AGC IN

PB AGC FILTER

PB AGC LEVEL ADJ

PB AGC DET IN

PB AGC OUT

GND

REC IN

REC FB + B

HEAD + B

HEAD – B

REC FB – B

GND

PB SW + OUT

PB SW – OUT

GND

REC FB – A

HEAD – A

HEAD + A

REC FB + A

VAMP

Balance Balance

BF

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VCC /GND pins

Pin No. Pin name Function

14

8

V

CC 4.9V

GND

REC current amplifier As above

38 37

VCC 4.9V

GND

PB amplifier, PB AGC, peak amplifier As above

47

5

VCC 4.9V

GND

PB first-stage amplifier PB first-stage amplifier, REC current amplifier

16 V

CC 3.0V Control logic

19 20 26

V

CC 4.9V

GND GND

Bias, REC limiter amplifier Bias, control logic REC limiter amplifier

∗

Make sure that the voltages at VCC and GND pins does not sway.

∗

Be especially careful of the VCC and GND for the first-stage amplifier.

∗

The playback system has high gain, so take care to ensure that the output does not find its way back to the input.

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Video ICs BH7272KV

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Electrical characteristics (unless otherwise noted, Ta = 25°C, VCC = 4.9V, 3.0V and f = 4.0MHz)

Parameter

Symbol

Min. Typ. Max.

Unit Conditions

Voltage gain ch-1

Voltage gain ch-2

GVP1

GVP2

50

54

58

dB

Pin 35 output measurement when pin 11 input is 0.3mV

P-P

Pin 35 output measurement when pin 2 input is 0.3mV

P-P

Frequency characteristics

Crosstalk

PB mute attenuation

AGC output level

AGC control sensitivity AGC frequency

characteristics

∆G

Vf

CTP

MUP

VAGC

∆VAGC

∆GVAF

—

230

—

280

0.2

—

330

2.0

—

dB

dBc

mV

P-P

dB

Pin 35 output level differential when f = 8.0 / 1.0MHz and V

IN = 0.3mVP-P

Pin 35 output level differential when for pin 45: H / L

Pin 35 output level differential when pin 33 goes from L to H and pin 2 input is 0.3mV

P-P

Pin 27 output measurement when pin 31 input is V

IN = 300mVP-P

Pin 27 output level differential when pin 31 input V

IN = 150 to 600mVP-P

Pin 27 output level differential when f = 8.0 /

1.0MHz and pin 31 input is V

IN = 300mVP-P

〈Playback system〉 Sleep-mode circuit current Circuit current

Iq

(S)

Iq (P)

— —

14 34

30 56

mAmANo signal

No signal

Voltage gain differential ∆G

VP —dB∆GVP = GVP1 – GVP2

∗

Note: dBc: dB below carrier (used to express relative level from carrier reference for convenience sake)

– 3.0

± 0.0

– 1.5

+ 1.5

– 3.0 ± 0.0

– 46

– 35

– 57 – 35

Recording current level 1

Recording current level 2

IOR1

IOR2

14

20

2626mAP-P

mAP-P

Pin 11 output measurement when pin 25 input is 0.3V

P-P

Pin 2 output measurement when pin 25 input is 0.3V

P-P

〈Recording system〉 Circuit current Iq

(R) — 54 80 mA No signal

REC mute attenuation 〈Logic system〉 PB holding voltage PB holding voltage REC holding voltage REC holding voltage HSW holding voltage HSW holding voltage RECGATE holding voltage RECGATE holding voltage

∆I

OF

MUR

VTH46H VTH46L VTH17H VTH17L VTH45H VTH45L VTH18H VTH18L

—

2.0

0.0

2.0

0.0

2.0

0.0

2.0

0.0

— — — — — — — —

– 35

3.0

1.0

3.0

1.0

3.0

1.0

3.0

1.0

dB

dBc

V V V V V V V V

f = 8.0 / 1.0MHz, pin 25 input = 0.3V

P-P

Pins 2, 11 output level differential

Pins 46 voltage to hold PB Pin 46 voltage to hold PB Pin 17 voltage to hold REC Pin 17 voltage to hold REC Pin 45 voltage to hold HSW Pin 45 voltage to hold HSW Pin 18 voltage to hold RECGATE Pin 18 voltage to hold RECGATE

– 3.0 ± 0.0

– 60

—

REC frequency characteristics

4

Video ICs BH7272KV

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Measurement circuit (playback system)

36 35 34 33 32 31 30 29 28 27 26 25

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18

17

16

15

14

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12

1110987654321

48

47

46

45

44

43

42

41

40

39

38

37

1k

Fig. 1

10k

3rd

2nd

AGC

DET

VAMP

IAMP

PRE

IAMPIAMP

PRE

IAMP

1k

10k

Bias

BH7272KV

LIMIT

LIMIT LEVEL adj

LIMIT Vth adj

Vcc 4.9V

REC GATE

REC “H”

Vcc 3.0V

Vcc 4.9V

I0adj

Vcc 4.9V

HEAD SW CTRL

PB “H”

Vcc 4.9V

I0adj

PB RF OUT

MUTE

AGC DET GATE

PB AGC IN

PB AGC OUT

0.1µ

50k

5.1k

REC IN

1000p

PRE IN B1

PRE IN B2

1000p

0.1µ

1k

10

0.1µ

1000p

PRE IN A1

PRE IN A2

1000p

0.1µ

1k

10

1000p

0.1µ

Balance Balance

BF

5

Video ICs BH7272KV

36 35 34 33 32 31 30 29 28 27 26 25

24

23

22

21

20

19

18

17

16

15

14

13

12

1110987654321

48

47

46

45

44

43

42

41

40

39

38

37

1k

10k

3rd

2nd

AGC

DET

VAMP

IAMP

PRE

IAMPIAMP

PRE

IAMP

1k

10k

Bias

BH7272KV

LIMIT

LIMIT LEVEL adj

LIMIT Vth adj

Vcc 4.9V

REC GATE

REC “H”

Vcc 3V

Vcc 4.9V

I0adj

Vcc 4.9V

HEAD SW CTRL

PB “H”

Vcc 4.9V

I0adj

PB RF OUT

MUTE

AGC DET GATE

PB AGC IN

PB AGC OUT

0.1µ

50k

5.1k

REC IN

1000p

0.1µ

1000p

1010

REC OUT A

REC OUT B

Fig. 2

Balance Balance

BF

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Measurement circuit (recording system)