ROHM BA7726AS, BA7726AFS Datasheet
1
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.
•
Features
1) Internal stereo line mixer amplifier, allowing selection 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.
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Applications
Portable CD stereos with karaoke functions, VCRs, mini component stereo systems, LD players
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Absolute maximum ratings (Ta = 25°C)
Parameter Symbol Limits Unit
Power supply voltage V
CC 14 V
Power dissipation
BA7726AS
mW
BA7726AFS
Operating temperature Topr °C
Storage temperature Tstg °C
1250
∗
1
850
∗
2
Pd
– 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 Symbol Min. Typ. Max. Unit
Power supply voltage V
CC 4.5 9.0 12.0 V
2
Multimedia ICs BA7726AS / BA7726AFS
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Block diagram
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32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17
10 11 12 13 14 15 16
OUTSW
VOCAL
FADER
SW
VOCAL
DET
ALC
VR
–
+
EXPAND
COMPRESS
–
+
–
+
VR
VR
BIAS
GND
VCC
LINE OUT R
LINE OUT L
L / VF / R CTRL
MUTE CTRL
LINE IN R
LINE IN L
VF LPF1
VF LPF2
LOOP GAIN CTRL
EXP DET
EXP DET CT
EXP BF IN
DLY BF OUT
L / ST / R CTRL
NO / VC CTRL
VO DET
VO DET LEVEL
ALC DET LEVEL
ALC DET
MIC AMP IN
MIC AMP NF
CMP DET
CMP DET CT
CMP OUT
CMP BF NF IN
CMP BF OUT
DLY BF NF IN
VF LPF3
ECHO LEVEL CTRL
3
Multimedia ICs BA7726AS / BA7726AFS
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Pin descriptions
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.
Pin No. Pin name Function Voltage Pin type
2, 1 LINE OUT L / R Line output (L, R) 4.5V EF (P - P)
3 L / VF / R CTRL
Line output switching (LEFT / VOCAL FADER / RIGHT)
2.5V
4 MUTE CTRL Line mute control input —
6, 5 LINE IN L / R Line input (L, R) 4.5V 100kΩ
7 VF LPF1 Vocal fader mode LPF capacitor 4.5V 23.5kΩ
8 VF LPF2 Vocal fader mode LPF capacitor 4.5V 70.5kΩ
9 VF LPF3
Vocal fader mode LPF capacitor
4.5V EF (NPN), 15kΩ
10 GND Ground 0.0V —
11 ECHO LEVEL CTRL Microphone off (ground to 0.1Vcc) / echo level adjustment (0.2Vcc to Vcc) —
12 LOOP GAIN CTRL Loop attenuation ratio setting —
13 EXP DET Expand detection wave 4.5V 50kΩ
14 EXP DET CT
Expand attack / recovery time setting
Attack R = 5.6kΩ , recovery R = 85.6kΩ
—
15 EXP BF IN BF input 4.5V B (NPN)
16 DLY BF OUT LPF BF output (EXP) 4.5V EF (NPN)
17 DLY BF NF IN LPF BF negative feedback input (EXP) 4.5V B (NPN)
18 CMP BF OUT LPF BF output (CMP) 4.5V EF (P - P)
19 CMP BF NF IN LPF BF negative feedback input (CMP) 4.5V B (NPN)
20 CMP OUT Compression output 4.5V EF (NPN)
21 CMP DET CT
Compression attack / recover time setting
Attack R = 5.6kΩ, recovery R = 85.6kΩ
—
22 CMP DET Compression detection wave 4.5V 60kΩ
23 V
CC
V
CC
9.0V —
24 BIAS Bias and capacitor for ripple rejection 4.5V 23.5kΩ
25 MIC AMP NF Microphone amplifier negative feedback 4.5V 2kΩ
26 MIC AMP IN Microphone amplifier input 4.5V 100kΩ
27 ALC DET ALC attack / recovery time setting — 220Ω
28 ALC DET LEVEL ALC level setting — B (PNP)
29 VO DET LEVEL Microphone amplifier input detection level setting — B (PNP)
30 VO DET Microphone amplifier input detection attack / recover time setting — 1kΩ
31 NO / VC CTRL Line output switching (NORMAL / VOCAL CUT) —
32 L / ST / R CTRL Line output switching (LEFT / STEREO / RIGHT) 2.5V
—
—
All figures are designed values based on the measurement circuit in Fig. 1 (where Vcc = 9.0V), and are not guaranteed standards.
∗
∗
∗
∗
∗
∗
4
Multimedia ICs BA7726AS / BA7726AFS
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Input / output circuits
∗ All figures are designed values, and are not guaranteed standards.
VCC
3.3V
1.7V
3
VCC
85k
15k
11
39k
31
VCC
49.5k
33k
VCC
3.3V
1.7V
39k
0.6 × V
CC
0.8 × VCC
0.6 × VCC
0.8 × VCC
12
32
2.5V
150k
4
39k
39k 39k
39k 39k
39k
L / VF / R CTRL MUTE CTRL
LOOP GAIN CTRLECHO LEVEL CTRL
NO / VC CTRL L / ST / R CTRL
VCC
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