BA7726AS_技术文档

Multimedia ICs

Analog compander with vocal fader

for KARAOKE

BA7726AS / BA7726AFS

The BA7726AS and BA7726AFS are analog companders for karaoke echo systems and have internal logarithmic

compression and expansion circuits, a stereo line mixer amplifier, vocal fader function, vocal detection function,

microphone ALC, microphone ON / OFF switch, and output switch. When used together with the BU9252 8-bit digital

delay, these ICs form a high-grade karaoke echo system with minimum components.

Applications

•

Portable CD stereos with karaoke functions, VCRs, mini component stereo systems, LD players

Features

•

1) Internal stereo line mixer amplifier, allowing selec-

tion of through output, left output, or right output.

2) Internal vocal elimination function, suitable for vocal

faders and left and right output.

4) Internal microphone ON / OFF switch.

5) Vocal detection.

6) Internal microphone ALC function.

7) Internal anti-popping circuit.

3) Echo level and loop ratio are DC-adjustable with the

internal electronic volume control (EVR).

Absolute maximum ratings (Ta = 25°C)

•

Parameter

Symbol

V^CC

Limits

14

Unit

Power supply voltage

V

1

BA7726AS

BA7726AFS

– 10 ~ + 70

– 55 ~ + 125

1250

Power dissipation

Pd

mW

2

850

Operating temperature

Storage temperature

Topr

Tstg

°C

1 Reduced by 12.5mW for each increase in Ta of 1°C over 25°C.

2 Reduced by 8.5mW for each increase in Ta of 1°C over 25°C.

Recommended operating conditions (Ta = 25°C)

•

Parameter

Symbol

V^CC

Min.

4.5

Typ.

9.0

Max.

12.0

Unit

Power supply voltage

V

1

Multimedia ICs

BA7726AS / BA7726AFS

Block diagram

•

32

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

VOCAL

DET

VR

ALC

–

COMPRESS

OUTSW

VOCAL

FADER

+

–

VR

SW

VR

EXPAND

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

2

Multimedia ICs

BA7726AS / BA7726AFS

Pin descriptions

•

Pin No.

Pin name

LINE OUT L / R

L / VF / R CTRL

MUTE CTRL

LINE IN L / R

VF LPF1

Function

Voltage

4.5V

2.5V

—

Pin type

2, 1

3

Line output (L, R)

EF (P - P)

Line output switching (LEFT / VOCAL FADER / RIGHT)

Line mute control input

4

6, 5

7

Line input (L, R)

4.5V

0.0V

—

100kΩ

23.5kΩ

Vocal fader mode LPF capacitor

8

VF LPF2

70.5kΩ

9

VF LPF3

EF (NPN), 15kΩ

—

Vocal fader mode LPF capacitor

Ground

10

11

12

13

GND

ECHO LEVEL CTRL Microphone off (ground to 0.1Vcc) / echo level adjustment (0.2Vcc to Vcc)

LOOP GAIN CTRL Loop attenuation ratio setting

—

EXP DET

Expand detection wave

4.5V

50kΩ

Expand attack / recovery time setting

Attack R = 5.6kΩ , recovery R = 85.6kΩ

14

EXP DET CT

—

15

16

17

18

19

EXP BF IN

DLY BF OUT

DLY BF NF IN

CMP BF OUT

CMP BF NF IN

BF input

4.5V

B (NPN)

EF (NPN)

B (NPN)

EF (P - P)

B (NPN)

LPF BF output (EXP)

LPF BF negative feedback input (EXP)

LPF BF output (CMP)

LPF BF negative feedback input (CMP)

20

21

CMP OUT

CMP DET CT

CMP DET

Compression output

4.5V

—

EF (NPN)

—

Compression attack / recover time setting

Attack R = 5.6kΩ, recovery R = 85.6kΩ

22

23

24

25

26

27

28

29

30

31

32

Compression detection wave

4.5V

9.0V

4.5V

—

60kΩ

—

VCC

V

CC

BIAS

Bias and capacitor for ripple rejection

Microphone amplifier negative feedback

Microphone amplifier input

23.5kΩ

2kΩ

MIC AMP NF

MIC AMP IN

ALC DET

100kΩ

220Ω

B (PNP)

1kΩ

ALC attack / recovery time setting

ALC DET LEVEL

VO DET LEVEL

VO DET

ALC level setting

—

Microphone amplifier input detection level setting

Microphone amplifier input detection attack / recover time setting

Line output switching (NORMAL / VOCAL CUT)

Line output switching (LEFT / STEREO / RIGHT)

—

NO / VC CTRL

L / ST / R CTRL

—

2.5V

Note: Pin type EF: emitter follower, P-P: push-pull, B: base

For pins marked with an asterisk ( ), refer to Input and output equivalent circuit.

All figures are designed values based on the measurement circuit in Fig. 1 (where Vcc = 9.0V), and are not guaranteed standards.

3

Multimedia ICs

BA7726AS / BA7726AFS

Input / output circuits

•

L / VF / R CTRL

MUTE CTRL

VCC

39k

1.7V

39k

3.3V

2.5V

4

150k

3

ECHO LEVEL CTRL

LOOP GAIN CTRL

VCC

12

11

85k

15k

39k

0.6 × V^CC

0.8 × VCC

39k

0.6 × VCC

0.8 × VCC

NO / VC CTRL

L / ST / R CTRL

VCC

49.5k

39k

31

39k

32

1.7V

3.3V

33k

All figures are designed values, and are not guaranteed standards.

4

Multimedia ICs

BA7726AS / BA7726AFS

Electrical characteristics (unless otherwise noted, Ta = 25°C, Vcc = 9.0V)

•

Parameter

Supply current

Symbol

I^CC

Min.

5.5

Typ.

8.4

Max.

12.7

Unit

mA

Conditions

No input

LINE THROUGH INPUT : LINE IN, OUTPUT : LINE OUT

Line through output level

Line through output distortion

Line through max. output level

Line through noise level

V^OLL

THD^LL

V^OMLL

V^ONLL

– 9.0

—

– 8.0

0.026

+ 10.0

– 100

– 7.0

0.2

dBV

%

VIN = – 20.0dBV

1

MIC OFF (V^ECHO= 0.1 × VCC)

1

+ 7.8

—

dBV

THD = 1%

2

No input, Rg = 1kΩ

MIC OFF (V^ECHO= 0.1 × VCC)

– 85

2

V^IN– 12dBV, Rg = 1kΩ

Interchannel crosstalk

Mute level

CT^LL

MT

—

– 85

—

dBV

MIC OFF (V^ECHO= 0.1 × VCC)

2

VIN = – 12dBV, Rg = 1kΩ

– 100

– 85

MIC OFF (V^ECHO= 0.1 × VCC)

MUTE (V^MUTE= H)

VOCAL CUT MODE INPUT : LINE IN, OUTPUT : LINE OUT

Through mode output level

Vocal suppression ratio 1

V^OLLV

V^OLL1

– 1.0

0.0

+ 1.0

dBV

dB

VIN = – 12dBV

V^IN= – 12dBV (single ch. in.),VOCAL FADER

(V^LSTR= H, VLVFR = OPEN, VNOVC = OPEN)

V^IN= – 12dBV (dual ch.in.),VOCAL FADER

(V^LSTR= H, VLVFR = OPEN, VNOVC = OPEN)

Vocal suppression ratio 2

V^OLL2

—

– 35

– 28

dB

MIC THROUGH INPUT : MIC AMP IN, OUTPUT : LINE OUT

Microphone through output level

VOML

– 9.9

– 8.4

– 6.9

dBV

VIN = – 38dBV

Microphone through

equivalent input noise

2

V^ONML

—

– 117

– 102

Rg = 1kΩ

2

V^IN= – 30dBV

Microphone input crosstalk

ALC level

CT^ML

—

– 92

– 77

dBV

MIC OFF (V^ECHO= 0.1 × VCC)

V^OAML

+ 5.1

+ 6.6

+ 8.1

V28 = 2.9V

COMPRESS INPUT : MIC AMP IN, OUTPUT : CMP BF OUT

Compress output level

V^OMC

CMP

– 5.5

—

– 3.5

+ 5.2

– 1.5

—

dBV

dB

VIN = – 38dBV

V^IN= – 43dBV → – 33dBV

Output level differential

Compress characteristics

EXPAND INPUT : DLY BF IN, OUTPUT : LINE OUT

Expand output level

V^ODL

EXP

– 9.4

—

– 7.4

—

dBV

dB

VIN = – 4dBV

Expand characteristics

+ 19.4

V^IN= – 9dBV → + 1dBV, Output level differential

V^IN= – 4dBV and when VIN = Vodl

ECHO LEVEL = Min. (V^ECHO= 0.2 × VCC)

Echo EVR attenuation ratio

∆VODL

—

– 50

– 40

dB

Loop INPUT : DLY BF IN, OUTPUT : CMP BF OUT

Loop output level

V^ODC

– 4.4

—

– 2.4

– 29

—

dBV

dB

VIN = – 4dBV

V^IN= – 4dBV and when VIN = Vodc

LOOP GAIN = Min. (VLOOP = 0.2 × VCC)

Loop EVR attenuation ratio

∆V^ODC

1

Unless otherwise noted, mode settings are as follows.

MUTE (V^MUTE= GND), STEREO (VNOVC = GND, VLSTR = OPEN, VLVFR = OPEN)

ECHO LEVEL = Max. (V^ECHO= VCC), LOOP GAIN = Max. (VLOOP = VCC)

Signal frequency : 1kHz, 1 : B.W. = 0.4 ~ 30kHz, 2 : DIN AUDIO

All parameters conform to the Measurement circuit diagram.

2

5

Multimedia ICs

BA7726AS / BA7726AFS

Parameter

Symbol

Min.

Typ.

Max.

Unit

Conditions

[ Control holding voltage ]

MUTE CTRL (4pin)

Mute holding voltage (4pin)

NO / VC CTRL (31pin)

VMUTE – L

GND

4.5

—

0.5

5.0

V

V^{MUTE – H}

Normal mode holding voltage

VOCAL CUT mode holding voltage

L / ST / R CTRL (32pin)

V^{NOVC – L}

GND

—

0.3 × VCC

V

V^{NOVC – H}0.5 × VCC

VCC

Left mode holding voltage

Stereo mode holding voltage

Right mode holding voltage

L / VF / R CTRL (3pin)

V^{LSTR – L}

V^{LSTR – M}

V^{LSTR – H}

GND

2.2

—

0.5

2.8

5.0

V

4.5

Left mode holding voltage

VOCAL FADER mode holding voltage

Right mode holding voltage

ECHO LEVEL CTRL (11pin)

MIC OFF holding voltage

MIC ON holding voltage

V^{LVFR – L}

V^{LVFR – M}

V^{LVFR – H}

GND

2.2

—

0.5

2.8

5.0

V

4.5

V^{ECHO – L}

GND

—

0.1 × VCC

V

V^{ECHO – H}0.2 × VCC

VCC

6

Multimedia ICs

BA7726AS / BA7726AFS

Measurement circuit

•

5600p 3900p

100µ

1k

1µ

10k

1k

0.47µ

39k

220p

18

18k

+

8.2k 6.8k

CMP BF OUT

DLY BF IN

A

3900p

+

1k

1µ

+

18k

47k 18k

32

31

30

29

28

27

26

25

24

23

22

21

20

19

17

VOCAL

DET

5600p

VR

ALC

–

+

COMPRESS

OUTSW

VOCAL

FADER

+

–

VR

SW

EXPAND

1

2

+

3

4

5

6

7

8

9

10

11

12

13

14

+

15

16

0.1µ

+

2.2µ 2.2µ

0.1µ

0.015µ

0.068µ

0.1µ 0.47µ

4700p 4700p

1k

10k

Fig. 1

7

Multimedia ICs

BA7726AS / BA7726AFS

Circuit operation

•

(1) MUTE CTRL (pin 4)

• Controls line muting.

(3) ECHO LEVEL CTRL and MIC ON / OFF SW (pin 11)

• Between Vcc and 0.2 × Vcc: Controls echo signal

mixing ratio

VMUTE (4pin)

Between Vcc and GND : Turns microphone input

sound (pin 26) to LINE OUT on and off

L

H

MUTE

V

ECHO (11pin)

VCC ~ 0.2 × VCC

0.1 × VCC ~ GND

MIC ON and ECHO LEVEL CTRL

MIC OFF

(2) OUTPUT CTRL (pins 3, 31, 32)

• LINE OUT output is controlled with pins 3, 31 and 32.

(Microphone mixing is controlled with pin 11.)

1) NO / VC CTRL (pin 31)

MIC AMP IN ~ LINE OUT

(VIN = – 38dBV, f = 1kHz)

• Used to select the NORMAL and VOCAL CUT modes.

0

DLY BF IN ~ LINE OUT

(V^IN= – 4dBV, f = 1kHz)

V^NOVC(31pin)

L

H

– 50

NORMAL

VOCAL CUT

NORMAL : Normal output mode. Controlled by pin 32.

VOCAL CUT : Used to erase or attenuate vocals in

multiplexed karaoke recordings and

normal stereo music recordings.

Controlled by pin3.

– 100

0.5

VECHO (11pin) P.P ratio : VECHO / VCC

1.0

0

Fig. 2 LINE OUTattenuation ratio vs. Vecho (11pin)

partial pressure ratio

These figures are for standard samples and

are not guaranteed standards.

2) L / ST / R CTRL (pin 32)

• Controls LINE OUT output in the NORMAL mode.

VLSTR (32pin)

(4) LOOP GAIN CTRL (pin 12)

L

M (OPEN)

STEREO

H

• Adjusts the loop gain (pins 17 and 18).

LEFT

RIGHT

LEFT

: LINE IN L input is output to LINE OUT L / R.

DLY BF IN ~ CMP BF OUT

STEREO : LINE IN L / R input is output to LINE OUT L / R without modification

RIGHT : LINE IN R input is output to LINE OUT L / R.

(V^IN= – 4dBV, f = 1kHz)

0

V^CC= 9.0V

– 25

3) L / VF / R CTRL (pin 3)

• Controls LINE OUT output in the VOCAL CUT mode.

– 50

VLVFR (3pin)

0.5

1.0

0

VLOOP (12pin) P.P ratio : VECHO / VCC

L

M (OPEN)

H

Fig. 3 CMP BF OUT attenuation ratio vs. Vloop

(pin 12) partial pressure ratio

LEFT

VOCAL FADER

RIGHT

LEFT

: For recordings in which the left channel is karaoke

and the right channel is for vocals (with karaoke).

These figures are for standard samples and

are not guaranteed standards.

VOCAL FADER : Attenuates the vocals from normal stereo recordings.

RIGHT

: For recordings in which the right channel is karaoke

and the left channel is for vocals (with karaoke).

When Vnovc = L, VLVFR = DON ' T CARE

When Vnovc = H, V^LSTR= DON ' T CARE

8

Multimedia ICs

BA7726AS / BA7726AFS

C2

R3

C1

(5) LPF

R1

TO BU9252

C2

• Use the internal operational amplifier and an

attached capacitor and resistor to configure a tertiary

LPF for anti-aliasing and smoothing.

C3

R1

FROM BU9252

R2

R1

C1

20

19

18

17

+

–

16

Fig. 4 LPF

LPF constant examples (V^CC

Cutoff frequency

= 9.0V)

R¹

LPF constant

Pass band gain

R2

R3

C1

C2

C3

2kHz

3kHz

4kHz

22kΩ

18kΩ

15kΩ

56kΩ

47kΩ

39kΩ

47kΩ

39kΩ

33kΩ

6800pF

5600pF

4700pF

3900pF

3300pF

270pF

220pF

180pF

0.6dB

0.7dB

0.8dB

CMP OUT (pin 20) output is positively correlated with Vcc. When Vcc is a voltage other than 9.0V, set the pass band gain so that maximum CMP side LPF output

(input to BU9252) is 5Vp-p. Make sure that the EXP side LPF constant does not exceed the load drive capability (minimum = 0.3mA, typical 0.5mA).

(6) Vocal fader function

between -4dBV and +9dBV, and is determined by the

voltage impressed on pin 28 (V²⁸, set with resistive

division between Vcc and the ground). ALC level is

calculated with the following equation, although slight

error occurs as V²⁸approaches VCC.

• After the synchronous component of the left and

right channels is eliminated, LPF output is added to

the signal, which is then output (see figure below).

The vocal component is difficult to remove from cer-

tain types of sources.

1

–

TO OUTSW

VOAML

Լ

× (V^CC– V28) [Vrms],

+

2 × 2

LPF

1.0 Ϲ V²⁸Ϲ 0.85 × (VCC – 1.0), at LINE OUT

5

6

7

8

9

C1

+ 10

V^CC= 9.0V

C2

LINE LINE

IN R IN L

at LINE OUT (f = 1kHz)

+ 5

Fig. 5 Vocal fader block

LPF constant examples

0

LPF constant

Cutoff frequency

C¹

C2

Set within this range

– 5

100Hz

150Hz

200Hz

0.022µF

0.015µF

0.01µF

0.1µF

0.068µF

0.047µF

– 10

0

5

10

C1 and C2 are only necessary when using the vocal fader function.

Pin 28 voltage: V28 (V)

(7) ALC level

Fig. 6 ALC level vs. pin 28 voltage

• When Vcc is 9.0V, ALC level can be set roughly

These figures are for standard samples and

are not guaranteed standards.

9

Multimedia ICs

BA7726AS / BA7726AFS

(8) Microphone input detection function

• This function detects the signal input to MIC AMP IN

(pin 26) and outputs it to pin 30.

Set within this range

– 20

V^CC= 9.0V

Pin 30 output

at MIC AMP IN (f = 1kHz)

No signal input to MIC AMP IN (pin 26)

Signal input to MIC AMP IN (pin 26)

GND

V^CC– 1.0V

– 70

• The detection level is determined by the voltage

impressed on pin 29 (V²⁹, set with resistive division

between Vcc and the ground) and is calculated with

the following equation, although slight error occurs

as V28 approaches ground.

0

5

10

Pin 29 voltage: V29 (V)

Fig. 7 Microphone amplifier input detection level vs.

pin 29 voltage

These are figures for standard samples and

are not guaranteed standards.

1

VODET Լ 0.03 × (

× V²⁹) [Vrms],

2 × 2

0.5 Ϲ V²⁹Ϲ 0.85 × (VCC – 1.0), at MIC AMP IN

Application example

•

1000p

8bit

A / D

1µ

0.1µ

39k

47k

S

and

H

+

3900p

18k

+

18k

+

220p

18 17

+

1µ

+

32

31

30

29

28

27

26

VR

25

24

23

22

21

20

19

VOCAL

DET

ALC

–

COMPRESS

OUTSW

VOCAL

FADER

+

–

VR

SW

VR

EXPAND

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

+

0.015µ

56k

BA7726AFS

0.068µ

10k

BU9252F

LOOP GAIN

2.7k

ECHO

LEVEL

Fig.8

10

Multimedia ICs

BA7726AS / BA7726AFS

Operation notes

•

(1) LINE OUT (pins 1 and 2) signal processing

• Be sure to attach a capacitor for phase correction to

the LINE OUT pins.

(2) Setting the loop gain

• Set the LPF constant and pin 12 control voltage so

that the loop gain (1st echo wave / 2nd echo wave)

does not exceed 1. Be particularly careful of peak-

ing near the LPF cutoff point.

LINE OUT R

(3) ALC function and microphone amplifier input

detection function

4700p

LINE OUT L

• Refer to items 7 and 8 in “Circuit description.” When

these functions are not used, be sure to ground pins

27 and 28 (the ALC function) and pins 29 and 30

(microphone amplifier input detection function).

4700p

Fig. 9

External dimensions (Units: mm)

•

BA7726AS

BA7726AFS

28.0 ± 0.3

13.6 ± 0.2

32

17

32

17

16

1

16

10.16

1

0.8

0.36 ± 0.1

0.3Min.

0.15

0° ~ 15°

1.778

0.5 ± 0.1

SDIP32

SSOP-A32

11


型号：	BA7726AS
厂家：	ROHM
描述：	Analog compander with vocal fader for KARAOKE 模拟压扩与声乐推子卡拉OK 卡拉OK
文件：	总11页 (文件大小：149K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

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