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Audio Accessory ICs
Preamps with Built-in ALC
BA3308F,BA3308FV
●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 Vrms)
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. BA3308F BA3308FV
Package SOP14 SSOP-B14
No.11087ECT01
Technical Note
2/9
BA3308F,BA3308FV
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●Absolute maximum ratings(Ta=25℃)
Parameter Symbol Limits Unit
Supply voltage VCC 16 V
Power
dissipation
BA3308F Pd 450*1 mW
BA3308FV 350*2
Operating temperature Topr －25～＋75 ℃
Storage temperature Tstg －55～＋125 ℃
*1 Reduce by 4.5 mW/C over 25C, when mounted on a 70mm×70mm×1.6mm PCB board.
*2 Reduce by 3.5 mW/C over 25C
●Operating conditions(Ta=25℃)
Parameter Symbol
Min. Typ. Max. Unit
Supply voltage VCC 4.5 - 14 V
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 Symbol Min. Typ. Max. Unit Conditions Test
Circuit
Quiescent current IQ 1.5 3.5 4.5 mA VIN=0Vrms Fig.17
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 k Fig.17
Maximum output voltage VOM 0.6 1.2 - Vrms THD=1% Fig.17
Input conversion noise
voltage VNIN - 1 2 Vrms Rg=2.2k, referenced to NAB 34dB
at 1kHz Fig.17
ALC range ALC 40 45 - dB Rg=3.9 k, VIN＝-70 dBV standard,
THD=3% Fig.17
ALC channel balance ALC - 0 2.5 dB VIN=-60dBV,-30dBV Fig.17
Channel separation CS 60 75 - dB VO=0dBV, NAB 34dB Fig.17
Technical Note
3/9
BA3308F,BA3308FV
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NF1
INPUT1
OUTPUT1
GND
ALC
V
CC
OUTPUT2
INPUT2
NF2
ALC
V
cc
1
2
3
4
5
6
7
14
13
12
11
10
9
8
N.C.
N.C.
N.C.
N.C.
N.C.
BA3308F/FV
●Block diagram
Fig.1
Technical Note
4/9
BA3308F,BA3308FV
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●Electrical characteristic curves (Reference data)
Fig.2 Quiescent current vs. Fig.3 Quiescent current vs. Fig.4 Voltage gain vs. frequency
power supply voltage ambient temperature
Fig.5 Total harmonic distortion vs. Fig.6 Voltage gain vs. Fig.7 Closed loop voltage gain vs.
frequency supply voltage ambient temperature
Fig.8 Input conversion noise voltage Fig.9 Channel separation vs. Fig.10 ALC characteristics
vs. signal source resistance frequency
Fig.11 Input/output characteristics Fig.12 Maximum output voltage vs. Fig.13 Maximum output voltage vs.
power supply voltage load resistance
Technical Note
5/9
BA3308F,BA3308FV
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●Description of operations
1. Recording
1) Record amplifier
2) ALC
Fig.5
BA3308
Cont ch2
(ch1)
ch2
(ch1)
ch1
(ch2)
2 (8) 1 (9) 3 (7) 5
3.9k
10F
INPUT
39
18k
1M
100F
10F
22F
OUTPUT
R
1
(R
2
)
R
3
(R
4
)
R
5
(R
6
)R
7
(R
8
)
C
1
(C
2
)
C
3
(C
4
)
C
5
(C
6
)
C
7
(C
8
)
Fig.14
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 k 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.
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.
13(9) 11(10) 1 (7) 4
Fig.6
ch2
(ch1)
ch2
(ch1)
ch1
(ch2)
ContComp
BA3308
3 (7) 52 (8)
4.5VF
VOUT (DCAC)
3VF
R
7
C
7
R
1
(R
2
)
Fig.15
1 (7) 4 13(9)
Technical Note
6/9
BA3308F,BA3308FV
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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/ (│＋jC9・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).
Fig.7
A1
BA3308
2 (8)
10μF
0.027μF
39
1 (9) 3 (7) 5
INPUT OUTPUT
R3
(R4)
C9
(C10)
(C6)
C5
10μF
(C2)
C1
100μF
(C4)
C3
R11
(R12)
4.3k
R9
(R10)
120k
13(9) 11(10) 1 (7) 4
Fig.16
Technical Note
7/9
BA3308F,BA3308FV
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© 2011 ROHM Co., Ltd. All rights reserved.
●Measurement circuit
●Application circuit
Fig.18
For playback, connect the following NAB time constant circuit between
pins 11 and 1 and pins 10 and 7 in place of R5 and R6.
INPUT1
INPUT2
1
2
3
4
5
6
78
9
10
11
12
13
14
ALC
10F
100F
100F
39
10F
330F
220
22F
VCC=7
3.9k
3.9k
10F
10F
R4
C4
R6
18k
C6
OUTPUT2
R8
1M
R7
C7
C8
18k
R5
C5
OUTPUT1
39
R3
R1
R2
C3
C2
C5
C9 (C10)
0.027F
R9 (R10)
120k
R11 (R12)
4.3k
Fig.17
1
2
3
4
5
6
7
8
9
10
11
12
13
14
ALC
V
V
V
V
V V
10k
10F
120k
1.2k 33k
0.1F
SW4A
100F
SW2A V2
22k 2
1 3 SW6A
30k INPUT1
SW3A
3.9k
3.9k SW3B
30k INPUT2
SW6B
SW1B
3
2
1
V2
2.2k
SW2B
100F
39
SW4B
2
1
0.1F
1.2k
120k
10F
10k
330F
220
SW5
22F
1M
VCC
OUTPUT1
OUTPUT2
2
1
33k
V1
V1
39
Fig.17
Technical Note
8/9
BA3308F,BA3308FV
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© 2011 ROHM Co., Ltd. All rights reserved.
●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.
Technical Note
9/9
BA3308F,BA3308FV
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© 2011 ROHM Co., Ltd. All rights reserved.
●Ordering part number
B A 3 3 0 8 F - E 2
Part No. Part No.
Package
F: SOP14
FV: SSOP-B14
Packaging and forming specification
E2: Embossed tape and reel
(Unit : mm)
SOP14
7
14
1.27
0.11
1
8
0.3MIN
8.7±0.2
0.4±0.1
0.15±0.1
1.5±0.1
6.2±0.3
4.4±0.2
(MAX 9.05 include BURR)
0.1
∗
Order quantity needs to be multiple of the minimum quantity.
<Tape and Reel information>
Embossed carrier tapeTape
Quantity
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
2500pcs
E2
()
Direction of feed
Reel 1pin
∗
Order quantity needs to be multiple of the minimum quantity.
<Tape and Reel information>
Embossed carrier tapeTape
Quantity
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
2500pcs
E2
()
Direction of feed
Reel 1pin
(Unit : mm)
SSOP-B14
8
7
14
1
0.10
6.4 ± 0.3
4.4
±
0.2
5.0 ± 0.2
0.22 ± 0.1
1.15 ± 0.1
0.65
0.15 ± 0.1
0.3Min.
0.1
R1120A
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Notes
No copying or reproduction of this document, in part or in whole, is permitted without the
consent of ROHM Co.,Ltd.
The content specied herein is subject to change for improvement without notice.
The content specied 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 specications,
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 specied 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 specied 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 specied in this document are intended to be used with general-use electronic
equipment or devices (such as audio visual equipment, ofce-automation equipment, commu-
nication devices, electronic appliances and amusement devices).
The Products specied 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, re or any other damage caused in the event of the
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The Products are not designed or manufactured to be used with any equipment, device or
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