Sony CXA1704R Datasheet

2-channel REC/PB Amplifier for 8mm VCR

Description

The CXA1704R is a bipolar IC designed as a recording/playback amplifier for Hi8-compatible VCRs.

Features

O Recording system

• Feedback damping provided in the recording

amplifier and its EVR control function facilitate

circuit board design.

• Y, chroma, and low-band level adjustment

functions

• Ramp circuit

O Playback system

• Feedback damping provided in the playback

amplifier facilitates circuit board design.

• Middle-frequency tuner on chip; EVR permits

independent adjustment of f0, Q and boost

• RF AGC and dropout detection circuit

Absolute Maximum Ratings (Ta=25°C)

• Supply voltage VCC 7V

•Operating temperature Topr –10 to +75 °C

• Storage temperature Tstg –65 to +150 °C

• Allowable power dissipation

Operating Conditions

Supply voltage

CXA1704R

48 pin LQFP (Plastic)

PD 1100 mW

(when board is mounted)

VCC 4.75

+0.5 V –0.25

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.

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E93860A66-TE

Block Diagram and Pin Configuration

CXA1704R

VCC1

REC1CONT

REC1OUT

PB1IN

GND1

PBDUMP1

PBDUMP2

GND2

PB2IN

REC2OUT

REC2CONT

VCC2

MTQ

25

26

27

28

29

30

31

32

33

34

35

36

REC

HEAD

REC

T3

2324

40dB

T2

RAMP

GEN

V/I

15dB

V/I

RAMP

GEN

RFSWP

22 21 20 19 18 17 16 15 14 13

T1

VPSW1

VPSW2

VCC

1CH 2CH MUTE

1CH(0dB) 1CH(6dB) 2CH(0dB) 2CH(6dB) MUTE

VIDEO PCM

RP_PB

PCMSW

VIDEOSW

YGCA

MTF0

1

2

M•T

–6dB

RF AGC

1

PCMOUT

AGCDET

LOWGCA

MTG2

MTGSW

12dB

1

MTOUT

DOCDET

1

CGCA

MTG1

DOP

12

DOCDET

11

RFAGCIN

10

RFAGCTC

9

RFAGCOUT

8

YLEVEL

7

YIN

6

LOWLEVEL

5

CIN

4

XGAIN

3

AFMIN

2

CCONT

1

37 38 39 40 41 42 43 44 45 46 47 48

IR

VG2

PCMIN

PCMREC

REC2IN

VPSW2OUT

VREG

REC1IN

VPSW1OUT

GND

IR1

—2—

ATFIN

Pin Description

Pin No. Symbol Pin voltage Equivalent circuit Description

CXA1704R

1 CCONT —

2 AFMIN —

32.5k

67.5k

60µ

25k

90µ

20p

50k

90µ

270

143

EVR adjustment of recording chroma level. Gain is small when the applied voltage is large.

1

Recording AFM input. DC is cut off by internal capacitor. Input level is 125 mVp-p (typ.). When not used, connect this pin to

2

Vcc.

3 XGAIN —

4 CIN 2.4 V

70µ

50k

35µ

143

VIDEO SW gain switch. Low : 6 dB High : 0 dB

143

3

Recording chroma input. Input the signal with capacitor coupling. Input level is 300 mVp-p (typ.).

4

—3—

Pin No. Symbol Pin voltage Equivalent circuit Description

CXA1704R

5 LOW LEVEL —

6 YIN 2.4 V

33.5k

66.5k

40µ

21k

90µ

50k

90µ

143

270

143

EVR adjustment of recording RF signal level. Gain is small when the applied voltage is large.

5

Adjusts both the VIDEO path and the PCM path simultaneously. VIDEO path: Adjustment of C + AFM + ATF PCM path: Adjustment of ATF

Recording Y signal input. Input the signal with capacitor coupling. Input level is 500 mVp-p (typ.).

6

7 YLEVEL —

8 RFAGCOUT 2.8 V

32.5k

67.5k

600µ

23k

90µ

40µ

270

90µ

EVR adjustment of recording Y signal level. The Y LEVEL is small when the applied voltage is large.

143

7

Playback Y signal output. Output level is 380 mVp-p (typ.).

8

—4—

Pin No. Symbol Pin voltage Equivalent circuit Description

CXA1704R

9 RFAGCTC —

10 RFAGCIN —

25µ

50µ

25µ

13p

50k

25µ

143

10

RF AGC time constant.

9

RF AGC input of playback Y level. The playback video signal output from Pin 14 (MTOUT) passes through an external ATF TRAP, AFM TRAP, and C TRAP, and is then input to Pin 10 (RFAGCIN) again. DC is cut off by internal capacitor. When not used, connect this pin to Vcc.

11 DOCDET 2.5 V

12 DOP H: 3.1 V

L: 0 V

50µ

46.5k

72k

47k

79k

100k

143

64k

11

150

2.4k

Determines the dropout detection level.

Dropout detection signal output. Goes high when a dropout is detected.

12

—5—

Pin No. Symbol Pin voltage Equivalent circuit Description

CXA1704R

13 MTG1 —

14 MTOUT 2.4 V

15 MTG2 —

40k

58k

40k

400µ

14k

90µ

14k

40µ

90µ

270

143

13

REVR adjustment of channel 1 middle-frequency tuner boost. Boost is small when the applied voltage is large.

Playback VIDEO output. Y + C + AFM + ATF is output.

14

EVR adjustment of channel 2 middle-frequency tuner boost. Boost is small when the applied voltage is large.

15

16 PCMOUT 2 V

17 MTF0 —

58k

33k

60k

400µ

90µ

41k

40µ

90µ

270

40µ

143

Playback PCM output.

16

EVR adjustment that determines f0 of the middle-frequency tuner. f0 is large when the applied voltage is large.

17

—6—

Pin No. Symbol Pin voltage Equivalent circuit Description

CXA1704R

18 RP_PB —

19 VCC 4.75 V

20 T1 —

35µ

REC/PB switch. High : PB Low : REC

143

18

Power supply for sections other than the REC amplifier and the PB amplifier. Connect to GND.

143

20

21 RFSWP —

22 T2 —

35µ

RFSWP input.

35µ

143

21

Connect to GND.

35µ

143

22

—7—

Pin No. Symbol Pin voltage Equivalent circuit Description

CXA1704R

23 T3 —

24 MTQ —

25 VCC1CH 4.75 V

26 REC1CONT —

30k

47k

34k

35µ

50k

40µ

71k

35µ

270

40µ

270

143

26

23

24

Connect to GND.

EVR adjustment that determines Q of the middle-frequency tuner. Q is large when the applied voltage is large.

Channel 1 power supply. EVR adjustment of recording channel 1 damping Damping is applied strongly when the applied voltage is small.

27 REC1CONT —

66k

5.7k

40µ

16.5k

40µ

1k

Recording channel 1 output. Open collector.

27

30

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