ROHM BA3308FV

Audio Accessory ICs
Preamps with Built-in ALC
BA3308F,BA3308FV
No.11087EBT01
●Description
The BA3308F/FV is a dual preamplifier for recording and playback with ALC (auto level control), developed for stereo radio,
cassette recorders, tape recorders, and other pre amplifiers audio applications.
ALC circuit has a build in rectification circuit with wide adjustable dynamic range, high gain, low distortion amplifiers with
direct coupling and mute circuit, used to cut off pop noise during power on.
Available in SOP14, or SSOP-B14 Packages.
●Features
1) Built-in ALC rectification diode
2) Wide operating power supply voltage range (VCC=4.5~14 V)
3) Low current consumption (IQ=3.5mA)
4) High gain (GVO=80dB)
5) Low distortion (THD=0.1%)
6) Low noise (VNIN=1 μVrms)
7) Input coupling capacitor not needed
8) Good ALC channel balance
9) Built-in power supply mute circuit
10) Dynamic range of ALC can be changed by attaching input resistance.
●Applications
Stereo radio, cassette tape recorders, stereo cassette decks, home stereos, music centers, etc.
●Line up matrix
Part No.
Package
BA3308F
BA3308FV
SOP14
SSOP-B14
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1/9
2011.08 - Rev.B
Technical Note
BA3308F,BA3308FV
●Absolute maximum ratings(Ta=25℃)
Parameter
Symbol
Supply voltage
VCC
BA3308F
Power
dissipation
BA3308FV
Operating temperature
Storage temperature
Limits
Unit
16
V
450*1
350*2
-25~+75
-55~+125
Pd
Topr
Tstg
mW
℃
℃
*1 Reduce by 4.5 mW/C over 25C, when mounted on a 70mm×70mm×1.6mm PCB board.
2
* Reduce by 3.5 mW/C over 25C
●Operating conditions(Ta=25℃)
Parameter
Symbol
Min.
Typ.
Max.
Unit
VCC
4.5
-
14
V
Supply voltage
Note: This IC is not designed to be radiation-resistant.
●Electrical characteristics(Unless otherwise noted, Ta=25℃, Vcc=7.0V, f=1kHz, BPF20~20kHz)
Parameter
Test
Circuit
Fig.17
Symbol
Min.
Typ.
Max.
Unit
IQ
1.5
3.5
4.5
mA
VIN=0Vrms
Open loop voltage gain
GVO
70
80
-
dB
VOUT=-10dBV
Fig.17
Total harmonic distortion
THD
-
0.1
0.3
%
NAB34dB, VOUT=40mVrms
Fig.17
Input resistance
RIN
15
25
45
kΩ
Maximum output voltage
Input conversion noise
voltage
VOM
0.6
1.2
-
Vrms
VNIN
-
1
2
μVrms
ALC
40
45
-
dB
ΔALC
-
0
2.5
dB
VIN=-60dBV,-30dBV
Fig.17
CS
60
75
-
dB
VO=0dBV, NAB 34dB
Fig.17
Quiescent current
ALC range
ALC channel balance
Channel separation
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2/9
Conditions
Fig.17
THD=1%
Rg=2.2kΩ, referenced to NAB 34dB
at 1kHz
Rg=3.9 kΩ, VIN=-70 dBV standard,
THD=3%
Fig.17
Fig.17
Fig.17
2011.08 - Rev.B
Technical Note
BA3308F,BA3308FV
●Block diagram
BA3308F/FV
14 N.C.
OUTPUT1 1
GND
2
N.C.
3
ALC
ALC
4
V CC
5
N.C.
6
OUTPUT2


13 INPUT1
12 N.C.
11 NF1


V cc
7
10 NF2
9
INPUT2
8
N.C.
Fig.1
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3/9
2011.08 - Rev.B
Technical Note
BA3308F,BA3308FV
●Electrical characteristic curves (Reference data)
Fig.2 Quiescent current vs.
power supply voltage
Fig.5 Total harmonic distortion vs.
frequency
Fig.8 Input conversion noise voltage
vs. signal source resistance
Fig.11 Input/output characteristics
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Fig.3
Quiescent current vs.
ambient temperature
Fig.6 Voltage gain vs.
supply voltage
Fig.4 Voltage gain vs. frequency
Fig.7 Closed loop voltage gain vs.
ambient temperature
Fig.9 Channel separation vs.
frequency
Fig.10 ALC characteristics
Fig.12 Maximum output voltage vs.
power supply voltage
Fig.13 Maximum output voltage vs.
load resistance
4/9
2011.08 - Rev.B
Technical Note
BA3308F,BA3308FV
●Description of operations
1. Recording
1) Record amplifier
BA3308
ch2
(ch1)
Cont
The BA3308F/FV amplifier of ch1 and ch2 input stage
(13pin, 9pin) can be direct coupled or use coupling
capacitors (C1/C2). The voltage gain of the record amplifier
is determined by GV=R5/R3. The R5/R6, and C3/R3 regulate
control of the pop noise that occurs at power-on (see
“Cautions on use”) and direct current bias fed back is set by
R5/R6 and C5/C6 at the output stage.
ch2
(ch1)
ch1
(ch2)
2 (8)
13(9)
R1
(R2)
3.9k
C1
(C2)
10F
1 (9)
11(10)
45
31 (7)
R5
(R6)
18k
R3
(R4)
39
R7
(R8)
1M
C7
(C8)
22F
C5
(C6)
10F
C3
(C4)
100F
INPUT
OUTPUT
Fig.14
Fig.5
2) ALC
The BA3308F/FV has an on-chip signal rectifier and electronic
volume needed for ALC. The signal rectifier compares the direct
current output voltage that is superposed in the output stage (1, 7pin)
signal to the reference voltage 4.5VF (≒3V; 1VF is approximately
0.7V) in the comparator circuit and if the output voltage is higher, it
turns the comparator ON to charge the smoothing capacitor C7.
Since the operation point of the output stage of amplifier ch1 and ch2
is fixed at 3VF, the comparator turns ON when the peak value of the
signal output voltage is 1.5VF (effective value approx. 0.75V). Once
the direct current signal for electronic volume is controlled, ALC
operation starts. The electronic volume, which is connected between
the input line (13, 9pin) and GND, causes the input signal to
attenuate according to the ratio of the external resistance (R1, R2) to
the resistance value of the electronic volume. The ALC range varies
according to the values of R1 and R2. For small ALC variation the
S/N will determinate an adequate ALC range is obtained by applying
several kΩ of the R1 and R2. The attack time and recovery time of
ALC are set according to C7 and R7 of 4pin. If the time constants
(C7, R7) are large, the recovery time will be long and as C7 becomes
smaller, and the attack time will be shorter.
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5/9
ch1
(ch2)
ch2
(ch1)
Comp
ch2
(ch1)
Cont
4.5VF
BA3308
VOUT (DCAC)
1 (7)
4
3 (7)
13(9)
5
2 (8)
3VF
R7
C7
Fig.15
Fig.6
2011.08 - Rev.B
R1
(R2)
Technical Note
BA3308F,BA3308FV
2.
On playback
Since
amplifier ch1 and ch2 are used as a NAB equalizer
.
amplifier at playback, a time constant circuit is established in
the NF section (1-11pin, 7-10pin) to obtain NAB
characteristics. The voltage gain at this time is determined by
the following formula:
GV = │R11+R9/ (│+jωC9・R9)│/R3
Obtain the necessary gain by regulating the (power-on pop
noise prevention) NAB time constant circuit in the same way
when regulating the gain at recording stage. The operating
point of the output stage (1,7pin) is fixed at 3VF.
Accordingly, even if VCC is raised to 5V or more, as in the
VMAX-VCC characteristic (Fig.13), the maximum output voltage
does not rise above 1.2V (Typ.). 4pin is grounded at playback
since ALC is not needed. For better signal-to-noise ratio
characteristics at playback, don’t use R1 and R2, which are
attached to the input pin (13pin, 9pin).
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BA3308
A1
13(9)
2 (8)
11(10)
1 (9)
R3
(R4)
39
C1
(C2)
10μF
R11
(R12)
4.3k
C9
0.027μF
(C10)
C3
(C4)
100μF
INPUT
R9
(R10)
120k
31 (7)
(7)
45
C5
(C6)
10μF
OUTPUT
Fig.16
Fig.7
2011.08 - Rev.B
Technical Note
BA3308F,BA3308FV
●Measurement circuit
V
10k
100μF
22k
OUTPUT1
10μF
1
120k
1.2k
39Ω
V
SW2A
V
SW6A
3
V1
V2
33k
2
2
1
INPUT1
30k
SW4A
0.1μF
1
14
2
13
1M
3
SW5
22μF
220Ω
330μF
3.9k
SW3B
11
5
10
6
9
7
8
1.2k
SW3A
12
ALC
4
VCC
3.9k
0.1μF
2
SW4B
30k
33k
1
120k
10μF
39Ω
SW2B
V2
V
10kΩ
3
1
OUTPUT2
V
100μF
2.2k
INPUT2
SW6B
2
SW1B
V
V1
Fig.17
●Application circuit
OUTPUT1
C5
10μF
C3
R3
R5
100μF
39Ω
18kΩ
R7
1MΩ
C7
22μF
1
14
2
13
3
12
ALC
4
VCC=7V
330μF
220Ω
C8
3.9kΩ
C5
INPUT1
10μF
11
5
R8
R1
10
6
9
7
8
R2
3.9kΩ
C2
INPUT2
10μF
R6
18kΩ
C6
R4
39Ω
10μF
OUTPUT2
R11 (R12)
4.3kΩ
C4
R9 (R10)
120kΩ
100μF
For playback, connect the following NAB time constant circuit between
C9 (C10)
pins 11 and 1 and pins 10 and 7 in place of R5 and R6.
0.027μF
Fig.18
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7/9
2011.08 - Rev.B
Technical Note
BA3308F,BA3308FV
●Notes for use
1) Numbers and data in entries are representative design values and are not guaranteed values of the items.
2) Although ROHM is confident that the example application circuit reflects the best possible recommendations, be sure
to verify circuit characteristics for your particular application. Modification of constants for other externally connected
circuits may cause variations in both static and transient characteristics for external components as well as this Rohm
IC. Allow for sufficient margins when determining circuit constants.
3) Absolute maximum ratings
Use of the IC in excess of absolute maximum ratings, such as the applied voltage or operating temperature range
(Topr), may result in IC damage. Assumptions should not be made regarding the state of the IC (short mode or open
mode) when such damage is suffered. A physical safety measure, such as a fuse, should be implemented when using
the IC at times where the absolute maximum ratings may be exceeded.
4) GND potential
Ensure a minimum GND pin potential in all operating conditions. Make sure that no pins are at a voltage below the
GND at any time, regardless of whether it is a transient signal or not.
5) Thermal design
Perform thermal design, in which there are adequate margins, by taking into account the permissible dissipation (Pd) in
actual states of use.
6) Short circuit between terminals and erroneous mounting
Pay attention to the assembly direction of the ICs. Wrong mounting direction or shorts between terminals, GND, or other
components on the circuits, can damage the IC.
7) Operation in strong magnetic fields
Using the ICs in a strong electromagnetic field can cause operation malfunction.
8) The BA3308F/FV has an on-chip power supply mute circuit that checks for pop noise at power-on. This prevents the
occurrence of pop noise by timing the charge times of the direct current cut capacitors C3 and C4 of 10pin and 11pin,
and of capacitor C8 for the ripple filter of 5pin.
Accordingly, to obtain an adequate effect, it is recommended that the constants of the application circuit be used in C3,
C4, R3, R4, C8, and R8.
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8/9
2011.08 - Rev.B
Technical Note
BA3308F,BA3308FV
●Ordering part number
B
A
3
Part No.
3
0
8
F
Part No.
-
Package
F: SOP14
FV: SSOP-B14
E
2
Packaging and forming specification
E2: Embossed tape and reel
SOP14
<Tape and Reel information>
8.7 ± 0.2
(MAX 9.05 include BURR)
8
Tape
Embossed carrier tape
Quantity
2500pcs
E2
Direction
of feed
The direction is the 1pin of product is at the upper left when you hold
( reel on the left hand and you pull out the tape on the right hand
0.3MIN
4.4±0.2
6.2±0.3
14
1
)
7
1.5±0.1
0.15 ± 0.1
0.4 ± 0.1
0.11
1.27
0.1
1pin
Direction of feed
∗ Order quantity needs to be multiple of the minimum quantity.
Reel
(Unit : mm)
SSOP-B14
<Tape and Reel information>
5.0 ± 0.2
8
0.3Min.
4.4 ± 0.2
6.4 ± 0.3
14
1
Tape
Embossed carrier tape
Quantity
2500pcs
Direction
of feed
E2
The direction is the 1pin of product is at the upper left when you hold
( reel on the left hand and you pull out the tape on the right hand
)
7
0.10
1.15 ± 0.1
0.15 ± 0.1
0.65
0.1
0.22 ± 0.1
1pin
Reel
(Unit : mm)
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9/9
Direction of feed
∗ Order quantity needs to be multiple of the minimum quantity.
2011.08 - Rev.B
Notice
Notes
No copying or reproduction of this document, in part or in whole, is permitted without the
consent of ROHM Co.,Ltd.
The content specified herein is subject to change for improvement without notice.
The content specified herein is for the purpose of introducing ROHM's products (hereinafter
"Products"). If you wish to use any such Product, please be sure to refer to the specifications,
which can be obtained from ROHM upon request.
Examples of application circuits, circuit constants and any other information contained herein
illustrate the standard usage and operations of the Products. The peripheral conditions must
be taken into account when designing circuits for mass production.
Great care was taken in ensuring the accuracy of the information specified in this document.
However, should you incur any damage arising from any inaccuracy or misprint of such
information, ROHM shall bear no responsibility for such damage.
The technical information specified herein is intended only to show the typical functions of and
examples of application circuits for the Products. ROHM does not grant you, explicitly or
implicitly, any license to use or exercise intellectual property or other rights held by ROHM and
other parties. ROHM shall bear no responsibility whatsoever for any dispute arising from the
use of such technical information.
The Products specified in this document are intended to be used with general-use electronic
equipment or devices (such as audio visual equipment, office-automation equipment, communication devices, electronic appliances and amusement devices).
The Products specified in this document are not designed to be radiation tolerant.
While ROHM always makes efforts to enhance the quality and reliability of its Products, a
Product may fail or malfunction for a variety of reasons.
Please be sure to implement in your equipment using the Products safety measures to guard
against the possibility of physical injury, fire or any other damage caused in the event of the
failure of any Product, such as derating, redundancy, fire control and fail-safe designs. ROHM
shall bear no responsibility whatsoever for your use of any Product outside of the prescribed
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The Products are not designed or manufactured to be used with any equipment, device or
system which requires an extremely high level of reliability the failure or malfunction of which
may result in a direct threat to human life or create a risk of human injury (such as a medical
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R1120A