Transcript
Multimedia ICs
Microphone Amplifier BA7760 / BA7760F The BA7760 and BA7760F are dual microphone amplifiers designed for audio signal amplification. These are low noise amplifiers with a low -122dBV (typically) equivalent input noise voltage. Each IC has an internal mixer buffer amplifier for the mixing of signals from two channels. When used with the BA7725S or BA7725FS, the BA7726AS or BA7726AFS and BU9252S or BU9252F, these ICs simplify the configuration of digital echo systems with two inputs (for karaoke duets, for instance).
Applications •Audio equipment with karaoke features, VCRs, LDs, etc.
•1)Features Internal 2-channel low noise microphone amplifier. 2) Internal mixer buffer amplifier with mute function. 3) Available in 2 types of packages: DIP 14-pin or SOP 14-pin.
•Absolute maximum ratings (Ta = 25°C) Parameter
Symbol
Limits
Unit
VCC
15
V
Applied voltage Power dissipation
BA7760
Pd
BA7760F
600∗1
mW
450∗2
Operating temperature
Topr
– 25 ~ + 75
°C
Storage temperature
Tstg
– 55 ~ + 125
°C
∗1 Unmounted. Reduced by – 6.0mW for each increase in Ta of 1°C over 25°C. ∗2 Unmounted. Reduced by – 4.5mW for each increase in Ta of 1°C over 25°C.
•Recommended operating conditions Parameter
Symbol
Limits
Unit
Power supply voltage
VCC
6 ~ 14
V
1
Multimedia ICs
BA7760 / BA7760F
1 RIPPLE FILTER
3 MIC IN Ch1 ( + ) MIC IN Ch2 ( + ) 12
2 GND
4 MIC IN Ch1 ( – ) MIC IN Ch2 ( – ) 11
5 FILTER Ch1
7 MIX IN
6 MIC OUT Ch1
•Block diagram
–
MIC AMP CH 1 MIC AMP CH 2 +
MIX BF +
+
–
VCC 14
MUTE CTRL 13
FILTER Ch2 10
MIC OUT Ch2 9
MIX OUT 8
–
•Pin descriptions Pin name
Pin No.
Pin type
Function
1
RIPPLE FILTER
Ripple filter
2
GND
GND
3
MIC IN ( + ) Ch1
CH1 microphone amplifier input ( + )
Base (NPN) // 120kΩ
4
MIC IN ( – ) Ch1
CH1 microphone amplifier input ( – )
Base (NPN)
5
FILTER Ch1
CH1 microphone amplifier fc
Base (NPN) ~ 450Ω
6
MIC OUT Ch1
CH1 microphone amplifier output
Push-pull
7
MIX IN
Mixer buffer input
Base (NPN) // 65kΩ
8
MIX OUT
Mixer buffer output
Push-pull
9
MIC OUT Ch2
CH2 microphone amplifier output
Push-pull
10
FILTER Ch2
CH2 microphone amplifier fc
Base (NPN) ~ 450Ω
11
MIC IN ( + ) Ch2
CH2 microphone amplifier input ( – )
Base (NPN)
12
MIC IN ( – ) Ch2
CH2 microphone amplifier input ( + )
Base (NPN) // 120kΩ
13
MUTE CTRL
Mute control
Fig.1
14
VCC
VCC
Base (NPN) // 15kΩ —
—
∗ “Parallel” and “series” respectively refer to parallel and series insertion. All figures are standard values.
2
Multimedia ICs
BA7760 / BA7760F
•Input / output circuits 40kΩ MUTE CTRL 13
Fig. 1
•Electrical characteristics (unless otherwise noted, Vcc = 12V, Ta = 25°C) Parameter Supply current
Symbol
Min.
Typ.
Max.
Unit
Conditions
Iq
3.65
4.87
6.09
mA
—
〈MIC AMP (GVC= 36dB, f = 1kHz)〉 Open loop voltage gain
GVOM
55.0
Input conversion noise
VnM
—
65.0
—
– 122
– 114
Distortion
THDM
—
0.008
0.1
%
VIN = – 40dBV B.W. = 0.4 ~ 30kHz
Maximum output level
VomM
8.3
10.4
—
dBV
THD = 1% B.W. = 0.4 ~ 30kHz
Input impedance
ZinM
92
123
—
kΩ
Crosstalk
CTM
—
Voltage gain
GVB
– 0.7
Output residual noise
VnB
—
Distortion
THDB
—
0.002
0.07
%
VIN = – 10dBV B.W. = 0.4 ~ 30kHz
Maximum output level
VOMB
8.3
10.5
—
dBV
THD = 1% B.W. = 0.4 ~ 30kHz
Input impedance
ZinB
50.0
66.5
—
kΩ
– 110
– 100
2.62
3.12
– 86
– 78
dB dBV
dBV
VIN = – 70dBV Rg = 2.2kΩ, DIN AUDIO
VIN = – 40dBV, 100kΩAttenuation VIN = – 36dBV Rg = 2.2kΩ, DIN AUDIO
〈MIX BF (f = 1kHz)〉
Mute level Mute threshold voltage
MTB
—
VTHMUTE
2.12
0 – 110
0.7 – 100
dB dBV
dBV V
VIN = – 10dBV Rg = 2.2kΩ, DIN AUDIO
VIN = – 10dBV, 50kΩAttenuation VIN = – 10dBV, DIN AUDIO —
3
Multimedia ICs
BA7760 / BA7760F
•Measurement circuit +
10
–
+
5kΩ
MIC OUT Ch1
4.7µF
6 150pF
MIC AMP Ch1
150pF
13.9kΩ
9
1MΩ
7
–
MIC AMP Ch2
MIC OUT Ch2
10µF
+
5
–
1MΩ
8 5kΩ
+
13.9kΩ
MIX OUT
MIX BF
MIX IN
2.2kΩ
10kΩ
470µF +
470µF + 11
4
220Ω
220Ω
+
12
3
+
+ 47µF
4.7µF
MIC IN Ch1
MIC IN Ch2
+ 47µF
4.7µF 2.2kΩ
MUTE CTRL
13
2
VCC
2.2kΩ
14
1
+ 22µF
BA7760 / F
Fig. 2
operation (Refer to “Application Example”) •TheCircuit BA7760 and BA7760F are dual microphone ampli-
(Note: The attached component numbers are those used in “Application Example.”)
60dB
40dB
C C 20dB
=
=
0
15
0p
F
0dB 180°
– 20dB
0° 3 61 3 61 3 61 3 61 3 61 – 180° 1kHz 10kHz 100kHz 1MHz 10MHz 100MHz FREQUENCY : f (Hz) Characteristics when using standard components and standard constants
Fig. 3 Microphone amplifier frequency characteristics
4
PHASE
VOLTAGE GAIN : GV (dB)
fiers. The audio signals from the microphones are input to pins 3 and 12. The gain at this time is determined by attached resistors R3 / R4 and R6 / R7. By attaching capacitors to pins 5 and 10, the microphone amplifiers can be given frequency characteristics like those shown below.
Multimedia ICs
BA7760 / BA7760F
Output from these dual amplifiers is level-adjusted with an attached volume control (VR) and then input to pin 7 and mixed by the mixer buffer amplifier. The ON / OFF operation of the mixer buffer amplifier can be controlled with the signal input to pin 13 (MUTE CTRL). For DC loads, this volume control (VR) should be set above 4.5kΩ to assure proper performance of the IC’s internal driver.
Mode
Control signal
Operation
MUTE
L
Muted
MUTE
H
Normal operation
+
+
10µF
22kΩ
–
6
–
+
150pF
1µF
5 +
–
R7
+
+
220Ω
220Ω
+
+
3
12
47µF MICIN Ch1
4.7µF
MICIN Ch2
47µF
R4
4
11
5kΩ (VR)
12kΩ
10
MIC AMP Ch1
150pF 12kΩ
R6
MIC AMP Ch2
9
1µF
+
+
5kΩ (VR)
7
R3
MIXOUT
MIX BF 8
0.1µF
10kΩ
0.1µF
22kΩ
•Application example
4.7µF 2.2kΩ
MUTE CTRL
2
14
1
+
13
VCC
2.2kΩ
22µF
BA7760 / F
Fig. 4
5
Multimedia ICs
BA7760 / BA7760F
•External dimensions (Units: mm) BA7760
BA7760F 19.4 ± 0.3
8.7 ± 0.2
8
3.2 ± 0.2
0.3 ± 0.1
2.54
0.5 ± 0.1
DIP14
6
14
8
1
7
1.27
0.15 ± 0.1
4.4 ± 0.2
6.2 ± 0.3
7.62
1.5 ± 0.1
7
0.51Min.
4.25 ± 0.3
1
0.11
6.5 ± 0.3
14
0.4 ± 0.1
0.3Min.
0° ~ 15° 0.15
SOP14
