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 with karaoke functions, VCRs, mini component stereo systems, LD players
Portable CD stereos
•
Features stereo line mixer amplifier, allowing selec-
1) Internal
tion of through output, left output, or right output.
2) Internal vocal elimination function, suitable for vocal
faders and left and right output.
3) Echo level and loop ratio are DC-adjustable with the
internal electronic volume control (EVR).
4) Internal microphone ON / OFF switch.
5) Vocal detection.
6) Internal microphone ALC function.
7) Internal anti-popping circuit.
•
Absolute maximum ratings (Ta = 25°C)
Parameter
Power supply voltage
Power dissipation
Operating temperature
Storage temperature
Symbol
V
CC
Pd
Topr
Tstg
Limits
14
BA7726AS
BA7726AFS
1250
∗
1
850
∗
2
Unit
V
mW
°C
°C
– 10 ~ + 70
– 55 ~ + 125
∗
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
Power supply voltage
Symbol
V
CC
Min.
4.5
Typ.
9.0
Max.
12.0
Unit
V
1
•
Block diagram
2
32
1
31
2
30
3
4
28
5
ALC
6
SW
7
8
9
10
GND
11
ECHO LEVEL CTRL
12
LOOP GAIN CTRL
13
EXP DET
14
EXP DET CT
15
EXP BF IN
16
DLY BF OUT
+ –
LINE OUT R
L / ST / R CTRL
Multimedia ICs
OUTSW
NO / VC CTRL
LINE OUT L
L / VF / R CTRL
VO DET
29
VOCAL
DET
MUTE CTRL
VO DET LEVEL
LINE IN R
ALC DET LEVEL
27
LINE IN L
ALC DET
26
VR
VF LPF1
MIC AMP IN
VOCAL
FADER
25
VF LPF2
MIC AMP NF
–
+
24
VF LPF3
BIAS
23
22
V
CC
COMPRESS
VR
VR
EXPAND
CMP DET
21
20
19
CMP DET CT
CMP OUT
CMP BF NF IN
–
+
BA7726AS / BA7726AFS
18
17
CMP BF OUT
DLY BF NF IN
Multimedia ICs
BA7726AS / BA7726AFS
•
Pin descriptions
Pin No.
2, 1
3
4
6, 5
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
Pin name
LINE OUT L / R
L / VF / R CTRL
MUTE CTRL
LINE IN L / R
VF LPF1
VF LPF2
VF LPF3
GND
Line output (L, R)
Line output switching (LEFT / VOCAL FADER / RIGHT)
Line mute control input
Line input (L, R)
Vocal fader mode LPF capacitor
Vocal fader mode LPF capacitor
Vocal fader mode LPF capacitor
Ground
Function
Voltage
4.5V
2.5V
—
4.5V
4.5V
4.5V
4.5V
0.0V
—
—
4.5V
—
4.5V
4.5V
4.5V
4.5V
4.5V
4.5V
—
4.5V
9.0V
4.5V
4.5V
4.5V
—
—
—
—
—
2.5V
Pin type
EF (P - P)
∗
∗
100kΩ
23.5kΩ
70.5kΩ
EF (NPN), 15kΩ
—
ECHO LEVEL CTRL Microphone off (ground to 0.1Vcc) / echo level adjustment (0.2Vcc to Vcc)
LOOP GAIN CTRL
EXP DET
EXP DET CT
EXP BF IN
DLY BF OUT
DLY BF NF IN
CMP BF OUT
CMP BF NF IN
CMP OUT
CMP DET CT
CMP DET
V
CC
BIAS
MIC AMP NF
MIC AMP IN
ALC DET
ALC DET LEVEL
VO DET LEVEL
VO DET
NO / VC CTRL
L / ST / R CTRL
Loop attenuation ratio setting
Expand detection wave
Expand attack / recovery time setting
Attack R = 5.6kΩ , recovery R = 85.6kΩ
BF input
LPF BF output (EXP)
LPF BF negative feedback input (EXP)
LPF BF output (CMP)
LPF BF negative feedback input (CMP)
Compression output
Compression attack / recover time setting
Attack R = 5.6kΩ, recovery R = 85.6kΩ
Compression detection wave
V
CC
Bias and capacitor for ripple rejection
Microphone amplifier negative feedback
Microphone amplifier input
ALC attack / recovery time setting
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)
∗
∗
50kΩ
—
B (NPN)
EF (NPN)
B (NPN)
EF (P - P)
B (NPN)
EF (NPN)
—
60kΩ
—
23.5kΩ
2kΩ
100kΩ
220Ω
B (PNP)
B (PNP)
1kΩ
∗
∗
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
V
CC
V
CC
MUTE CTRL
39k
3.3V
39k
1.7V
4
39k
2.5V
150k
3
ECHO LEVEL CTRL
LOOP GAIN CTRL
V
CC
12
85k
11
39k
39k
0.6
×
V
CC
0.8
×
V
CC
0.8
×
V
CC
15k
0.6
×
V
CC
NO / VC CTRL
L / ST / R CTRL
V
CC
V
CC
49.5k
39k
31
3.3V
33k
39k
39k
1.7V
32
∗
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
No input
Conditions
〈
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
Interchannel crosstalk
V
OLL
THD
LL
V
OMLL
V
ONLL
CT
LL
– 9.0
—
+ 7.8
—
—
– 8.0
0.026
+ 10.0
– 100
– 85
– 7.0
0.2
—
– 85
—
dBV
%
dBV
dBV
dBV
V
IN
= – 20.0dBV
V
IN
= – 20.0dBV
∗
1
MIC OFF (V
ECHO
= 0.1
×
V
CC
)
THD = 1%
∗
1
No input, Rg = 1kΩ
∗
2
MIC OFF (V
ECHO
= 0.1
×
V
CC
)
V
IN
– 12dBV, Rg = 1kΩ
∗
2
MIC OFF (V
ECHO
= 0.1
×
V
CC
)
V
IN
= – 12dBV, Rg = 1kΩ
∗
2
MIC OFF (V
ECHO
= 0.1
×
V
CC
)
MUTE (V
MUTE
= H)
Mute level
MT
—
– 100
– 85
dBV
〈
VOCAL CUT MODE
〉
INPUT : LINE IN, OUTPUT : LINE OUT
Through mode output level
Vocal suppression ratio 1
Vocal suppression ratio 2
V
OLLV
V
OLL1
V
OLL2
– 1.0
– 1.0
—
0.0
0.0
– 35
+ 1.0
+ 1.0
– 28
dBV
dB
dB
V
IN
= – 12dBV
V
IN
= – 12dBV (single ch. in.),VOCAL FADER
(V
LSTR
= H, V
LVFR
= OPEN, V
NOVC
= OPEN)
V
IN
= – 12dBV (dual ch.in.),VOCAL FADER
(V
LSTR
= H, V
LVFR
= OPEN, V
NOVC
= OPEN)
〈
MIC THROUGH
〉
INPUT : MIC AMP IN, OUTPUT : LINE OUT
Microphone through output level
Microphone through
equivalent input noise
Microphone input crosstalk
ALC level
V
OML
V
ONML
CT
ML
V
OAML
– 9.9
—
—
+ 5.1
– 8.4
– 117
– 92
+ 6.6
– 6.9
– 102
– 77
+ 8.1
dBV
dBV
dBV
dBV
V
IN
= – 38dBV
Rg = 1kΩ
∗
2
V
IN
= – 30dBV
∗
2
MIC OFF (V
ECHO
= 0.1
×
V
CC
)
V
28
= 2.9V
〈
COMPRESS
〉
INPUT : MIC AMP IN, OUTPUT : CMP BF OUT
Compress output level
Compress characteristics
V
OMC
CMP
– 5.5
—
– 3.5
+ 5.2
– 1.5
—
dBV
dB
V
IN
= – 38dBV
V
IN
= – 43dBV
→
– 33dBV
Output level differential
〈
EXPAND
〉
INPUT : DLY BF IN, OUTPUT : LINE OUT
Expand output level
Expand characteristics
Echo EVR attenuation ratio
V
ODL
EXP
∆V
ODL
– 9.4
—
—
– 7.4
+ 19.4
– 50
—
—
– 40
dBV
dB
dB
V
IN
= – 4dBV
V
IN
= – 9dBV
→
+ 1dBV, Output level differential
V
IN
= – 4dBV and when V
IN
= Vodl
ECHO LEVEL = Min. (V
ECHO
= 0.2
×
V
CC
)
〈
Loop
〉
INPUT : DLY BF IN, OUTPUT : CMP BF OUT
Loop output level
Loop EVR attenuation ratio
V
ODC
∆V
ODC
– 4.4
—
– 2.4
– 29
—
—
dBV
dB
V
IN
= – 4dBV
V
IN
= – 4dBV and when V
IN
= Vodc
LOOP GAIN = Min. (V
LOOP
= 0.2
×
V
CC
)
∗
1
Unless otherwise noted, mode settings are as follows.
MUTE (V
MUTE
= GND), STEREO (V
NOVC
= GND, V
LSTR
= OPEN, V
LVFR
= OPEN)
ECHO LEVEL = Max. (V
ECHO
= V
CC
), LOOP GAIN = Max. (V
LOOP
= V
CC
)
Signal frequency : 1kHz,
∗
∗
1 : B.W. = 0.4 ~ 30kHz,
∗
2 : DIN
AUDIO
2 All parameters conform to the Measurement circuit diagram.
5
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