BD3870FS_10 [ROHM]
Sound Processors with Built-in 3-band Equalizers; 声音处理器，内置3波段均衡器
| 型号： | BD3870FS_10 |
| 厂家： | 
ROHM |
| 描述： | Sound Processors with Built-in 3-band Equalizers |
| 文件： | 总16页 (文件大小：450K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Sound Processors for BOOM BOX / Mini-component Stereo
Sound Processors
with Built-in 2-band Equalizers
No.10086EAT02
BD3870FS,BD3871FS,BD3872FS,BD3873FS
●Description
The Sound Processor with built-in 2 Band Equalizer, incorporates functions required for BOOM BOX and mini-component
systems, such as input selector, input gain amp, volume, surround, tone (bass, treble), and loud speaker equalizer
(BD3872FS only). These functions can be controlled through the two-wire serial control.
●Features
1) Using external components, center frequencies and Q factors of the bass characteristics are flexible.
2) Providing a mute switch onto one of the input pins allows cross-talk suppression.
3) A surround function can be constructed without external components.
4) Energy-saving design resulting in low current consumption, by utilizing the BiCMOS process
●Applications
BOOM BOX, mini-audio systems, and micro-audio systems.
●Line up matrix
Parameter
BD3870FS
0, 6, 12, 18dB
No
BD3871FS
24, 26, 28dB
No
BD3873FS
18, 21, 24, 27dB
No
BD3872FS
0, 5, 10, 19, 21,
23, 26, 28dB
Input Gain
Loud Speaker Equalizer (SEQ)
Input Selector
Volume
Yes
Three inputs
Three inputs
Three inputs
Five inputs
0 to -87dB/
1dB step, -dB
0 to -87dB/
1dB step, -dB
0 to –87dB/
1dB step, -dB
0 to -87dB/
1dB step, -dB
2 band
(Bass, Treble)
2 band
(Bass, Treble)
2 band
(Bass, Treble)
2 band
(Bass, Treble)
Equalizer
Surround
Yes
Yes
Yes
Yes
Serial Control
Package
Two-wire serial
SSOP-A24
Two-wire serial
SSOP-A24
Two-wire serial
SSOP-A24
Two-wire serial
SSOP-A32
●Absolute maximum ratings (Ta=25℃)
Ratings
Prameter
Symbol
Unit
BD3870FS
BD3871FS
10
BD3873FS
10
BD3872FS
10
950 *2
Power Supply Voltage
Vcc
Pd
10
800 *1
V
mW
℃
Power Dissipation
800 *1
800 *1
Operating Temperature Range
Storage Temperature Range
Topr
Tstg
-25 to +75
-55 to +125
-25 to +75
-55 to +125
-25 to +75
-55 to +125
-25 to +75
-55 to +125
℃
*1 Reduced by 8.0 mW/℃ at 25℃ or higher, when installed on the standard board (Size: 70×70×1.6mm).
*2 Reduced by 9.5 mW/℃ at 25℃ or higher, when installed on the standard board (Size: 70×70×1.6mm).
●Operating voltage range
Ratings
Prameter
Symbol
Vcc
Unit
V
BD3870FS
4.5 to 9.5
BD3871FS
4.5 to 9.5
BD3873FS
4.5 to 9.5
BD3872FS
4.5 to 9.5
Operating Voltage Range
*It must function normally at Ta=25℃.
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© 2010 ROHM Co., Ltd. All rights reserved.
2010.10 - Rev.A
1/15
Technical Note
BD3870FS,BD3871FS,BD3872FS,BD3873FS
●Electrical characteristics
(Ta=25 ℃ , VCC=8V, f=1kHz, Vi=200mVrms, RL=10kΩ, Rg=600Ω, Input Gain=0dB (BD3870FS, BD3872FS only),
Input Gain=24dB (BD3871FS only), Input Gain=18dB (BD3873FS only),Volume=0dB, Bass=0dB, Treble=0dB,
Surround=OFF, Loud Speaker Equalizer=OFF (BD3872FS only), unless otherwise noted)
Limits
Parameter
Circuit Current
Symbol
IQ
Unit
mA
Condition
Min.
-
Typ.
8
Max.
21
At no signal
BD3870FS, BD3872FS
Gv=20log(VOUT/VIN)
-2
0
2
BD3871FS
Gv=20log(VOUT/VIN)
Total Output Voltage Gain
Gv
22
24
26
dB
BD3873FS
Gv=20log(VOUT/VIN)
16
-
18
0.01
2.1
20
0.1
-
Total Harmonic Distortion ratio
Maximum Output Voltage
THD
Vom
%
BW=400 to 30kHz
THD=1%
BW=400 to 30kHz
1.6
Vrms
BD3870FS, BD3872FS
Rg=0Ω, BW=IHF-A
-
-
-
-
4.5
40
15
80
Total Output Noise Voltage
Total Residual Noise Voltage
Vno
µVrms
µVrms
BD3871FS, BD3873FS
Rg=0Ω, BW=IHF-A
Rg=0Ω, BW=IHF-A
Volume=-dB
Rg=0Ω, BW=IHF-A
Vmno
4.5
-80
15
Cross-talk between Channels
Cross-talk between Selectors
CTC
CTS
-70
dB
dB
VOUT=1Vrms
-
35
70
-
-80
50
100
-
-70
65
130
50
-84
-90
73
16
-12
-
Rg=0Ω, BW=IHF-A
BD3870FS, BD3871FS, BD3873FS
BD3872FS
Input Impedance
Rin
kΩ
Output Impedance
Rout
VRI
Ω
Volume Control Range
Maximum Volume Attenuation
Volume Input Impedance
Bass Boost Gain
-90
-
-87
-
dB
dB
kΩ
dB
dB
dB
VR=20log(VOUT/VIN)
BW=IHF-A
Vmin
Rvin
GBB
GBC
BR
39
12
-16
-
56
14
-14
2
GB=20log(VOUT/VIN)
GB=20log(VOUT/VIN)
Bass Cut Gain
Bass Step Resolution
10
12
-14
-16
-
12
14
-12
-14
2
14
16
-10
-12
-
BD3870FS, BD3871FS, BD3873FS
BD3872FS
Treble Boost Gain
Treble Cut Gain
GTB
GTC
dB
dB
BD3870FS, BD3871FS, BD3873FS
BD3872FS
Treble Step Resolution
TR
dB
dB
dB
dB
Surround In-phase Gain
Surround Single-phase Gain
Vsur1
Vsur2
-2
4.3
8
0
2
2ch in-phase inputs
6.3
10
8.3
12
1ch input, 1ch grounded
2ch opposite-phase inputs
Surround Opposite-phase Gain Vsur3
Loud Speaker Equalizer Gain
Seq
3
5
7
dB
f=10kHz
(BD3872FS only)
*
*
*
For measurement, VP-9690A (Average value wave detection, Effective value display) IHF-A filter by Matsushita Communication Industrial is used.
Phase relation between Input/Output signal terminals is the same.
Note: This IC is not designed to be radiation-resistant.
www.rohm.com
2010.10 - Rev.A
2/15
© 2010 ROHM Co., Ltd. All rights reserved.
Technical Note
BD3870FS,BD3871FS,BD3872FS,BD3873FS
●Timing chart
1)Signal Timing Conditions
・Data is read on the rising edge of the clock.
・Latch is read out on the falling edge of the clock.
・Latch signal must end with the LOW state.
・To avoid malfunctions, clock and data signals must terminate with the LOW state.
1byte=10bit
90%
90%
90%
90%
10%
SC
(CLOCK)
tsu
twc
twc
10%
10%
thd
ts
th
tsd
thd
ts1
th1
SI
DATA
LATCH
90%
90%
90%
90%
90%
twh
tw1
twd
DATA
DATA
10%
LATCH
10%
10%
End with Low
Fig.1
Limits
Typ.
Parameter
Symbol
Unit
Min.
Max.
-
Minimum Clock Width
Minimum Data Width
Minimum Latch Width
Twc
twd
Tw1
Tsd
Thd
Ts1
Th1
Ts
2.0
2.0
2.0
1.0
1.0
1.0
1.0
1.0
2.0
-
-
-
-
-
-
-
-
-
µs
µs
µs
µs
µs
µs
µs
µs
µs
-
-
-
-
-
-
-
-
Data Set-up Time (DATACLK)
Data Hold Time (CLKDATA)
Latch Set-up Time (CLKLATCH)
Latch Hold Time (DATALATCH)
Latch Low Set-up Time
Latch Low Hold Width
Twh
2)Voltage Conditions for Control Signals
Parameter
Limits
Unit
Condition
Max.
(≦Vcc)
Min.
2.2
0
Typ.
“H” Input Voltage
“L” Input Voltage
-
-
5.5
V
V
Vcc=4.5 to 9.5V
Vcc=4.5 to 9.5V
1.0
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© 2010 ROHM Co., Ltd. All rights reserved.
2010.10 - Rev.A
3/15
Technical Note
BD3870FS,BD3871FS,BD3872FS,BD3873FS
3)Control Data Format List
Basic Configuration of Control Data Format
Data input direction
MSB
LSB
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
Select
Address
Data
Control Data Format (BD3870FS, BD3871FS, BD3873FS)
Data input direction
D9
D8
D7
D6
D5
D4
*
D3
*
D2
*
D1
D0
0
(1)
(2)
(3)
(4)
Input Selector
Input Gain
Volume A
Bass Gain
Surround
0
0
1
1
Volume B
Treble Gain
*
1
0
1
*
*
*
*
*
*
*
*
Control Data Format (BD3872FS)
Data input direction
D9
D8
D7
D6
D5
D4
D3
*
D2
*
D1
0
D0
0
(1)
(2)
(3)
(4)
Input Gain
Input Selector
Volume A
Volume B
Treble Gain
Surround SEQ
*
0
1
1
1
0
1
Bass Gain
*
*
*
*
*
*
・”*” indicates 0 or 1.
・By changing the setting of Select Address, three or four different control formats (BD3871FS, BD3872FS,
BD3873FS, plus BD3872FS) are selectable.
・In every power-on sequence, all of the address data must be initialized.
Example:
←Input direction
MSB
Data(1)
LSB MSB
LSB MSB
Data(3)
LSB MSB
Data(4)
LSB
L
L
Data(2)
L
L
“L” indicates a latch.
・After power-on, for the second and subsequent times, only the necessary data can be selected for setting.
Example: When changing the volume,
←Input direction
MSB
Data(2)
LSB
L
“L” indicates a latch.
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© 2010 ROHM Co., Ltd. All rights reserved.
2010.10 - Rev.A
4/15
Technical Note
BD3870FS,BD3871FS,BD3872FS,BD3873FS
●Block diagram, application circuit, pin assignment (BD3870FS, BD3871FS, BD3873FS)
5.6k
5.6k
DATA
LATCH
OUT2
OUT1
CLOCK
VCC
0.1μ
0.1μ
0.1μ
0.1μ
0.0022μ
0.33μ
0.0022μ
10μ
10μ
390k
390k
24
23
22
21
20
19
18
17
16
15
14
13
Logic
Treble1
fc=8kHz
Treble２
fc=8kHz
Bass2
f0=80Hz
Bass1
f0=80Hz
Vcc/2
Vcc/2
0dB
～
-87dB
-∞
Vcc/2
Vcc/2
Vcc/2
50k
50k
50k
50k
50k
50k
1
2
3
4
5
6
7
8
9
10
11
12
47μ
10μ
10μ
10μ
10μ
10μ
10μ
4.7k
10μ
10μ
4.7k
A1
A2
B1
B2
C1
C2
Unit: Resistance =Ω, Capacitor = F
Fig.2
●Pin description (BD3870FS, BD3871FS, BD3873FS)
Pin No. Pin Name Description
Pin No. Pin Name
Description
1
2
VIN1
VIN2
SEL2
SEL1
A1
1ch volume input pin
13
14
15
16
17
18
19
20
21
22
23
24
SC
SI
Serial clock input pin
2ch volume input pin
2ch input selector output pin
1ch input selector output pin
1ch input pin A
Serial data input pin
Power supply pin
2ch output pin
3
VCC
OUT2
OUT1
4
5
1ch output pin
6
A2
2ch input pin A
BOUT1 1ch bass filter setting pin
BNF1 1ch bass filter setting pin
BOUT2 2ch bass filter setting pin
7
B1
1ch input pin B
8
B2
2ch input pin B
9
C1
1ch input pin C
BNF2
TNF2
TNF1
CAP
2ch bass filter setting pin
2ch treble filter setting pin
1ch treble filter setting pin
10
11
12
C2
2ch input pin C
FILTER 1/2 VCC pin
GND Ground pin
Time constant setting pin for absorbing
surround switching shock sound
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© 2010 ROHM Co., Ltd. All rights reserved.
2010.10 - Rev.A
5/15
Technical Note
BD3870FS,BD3871FS,BD3872FS,BD3873FS
●Block diagram, application circuit, pin assignment (BD3872FS)
DATA CLOCK
LATCH
Vcc
OUT1 OUT2
0.0022μ
0.0022μ
5.6K
5.6K
0.001μ
0.001μ
0.1μ
0.1μ
0.1μ
0.1μ
0.022μ 62K
4.7μ
4.7μ
0.33μ
+
+
Vcc/2
31
Vcc/2
390K
390K
28
27
26
25
24
23
22
21
20
19
18
17
32
30
29
Logic
Loud
speaker
Loud speaker
equalizer2
Bass1
f0=80Hz
Bass2
f0=80Hz
Treble1
fc=10kHz
Treble2
fc=10kHz
Vcc/2
Vcc/2
Vcc/2
0dB
～
0dB
～
-87dB
-∞
-87dB
-∞
Vcc/2
Vcc/2
100k
100k
100k
100k
100k
100k
100k
100k
100k
100k
1
2
3
4
5
6
8
9
7
10
11
12
13
14
15
16
+
0.1μ
0.1μ
0.1μ
0.1μ
0.1μ
0.1μ
0.1μ
0.1μ
0.1μ
0.1μ
0.22μ
0.22μ
10μ
4.7k
4.7k
A1
A2
B1
B2
C1
C2
D1
D2
E1
E2
Unit: Resistance =Ω, Capacitor = F
Fig.3 Application to Cinema Surround
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© 2010 ROHM Co., Ltd. All rights reserved.
2010.10 - Rev.A
6/15
Technical Note
BD3870FS,BD3871FS,BD3872FS,BD3873FS
DATA CLOCK
LATCH
OUT1 OUT2
Vcc
0.0022μ
0.1μ
5.6K
0.33μ
0.01μ
0.33μ
0.01μ 0.0022μ
5.6K
0.1μ
0.1μ
0.1μ
4.7μ
4.7μ
0.33μ
+
+
390K
25
390K
23
28
27
26
24
22
21
20
19
18
17
32
31
30
29
Loud speaker
equalizer1
Logic
Loud speaker
equalizer2
Bass1
f0=80Hz
Bass2
f0=80Hz
Treble1
fc=10kHz
Treble２
fc=10kHz
Vcc/2
Vcc/2
Vcc/2
0dB
～
0dB
～
-87dB
-∞
-87dB
-∞
Vcc/2
Vcc/2
100k
100k
100k
100k
100k
100k
100k
100k
100k
100k
1
2
3
4
5
6
8
9
7
10
11
12
13
14
15
16
+
0.1μ
0.1μ
0.1μ
0.1μ
0.1μ
0.1μ
0.1μ
0.1μ
0.1μ
0.1μ
0.22μ
0.22μ
10μ
4.7k
4.7k
A1
A2
B1
B2
C1
C2
D1
D2
E1
E2
Unit: Resistance =Ω, Capacitor = F
Fig.4 Application to Loud Speaker Equalizer
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© 2010 ROHM Co., Ltd. All rights reserved.
2010.10 - Rev.A
7/15
Technical Note
BD3870FS,BD3871FS,BD3872FS,BD3873FS
●Pin description (BD3872FS)
Pin No. Pin Name
Description
Pin No. Pin Name
Description
Serial clock input pin
1
2
VIN1
SEL1
VIN2
SEL2
A1
1ch volume input pin
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
SC
SI
1ch input selector output pin
2ch volume input pin
2ch input selector output pin
1ch input pin A
Serial data input pin
Power supply pin
3
VCC
CAP
OUT2
OUT1
Time constant setting pin for absorbing
switching shock sound
4
5
2ch output pin
1ch output pin
6
A2
2ch input pin A
7
B1
1ch input pin B
BOUT2 2ch bass filter setting pin
BNF2 2ch bass filter setting pin
BOUT1 1ch bass filter setting pin
8
B2
2ch input pin B
9
C1
1ch input pin C
10
11
12
13
14
15
16
C2
2ch input pin C
BNF1
TNF2
TNF1
1ch bass filter setting pin
2ch treble filter setting pin
1ch treble filter setting pin
D1
1ch input pin D
D2
2ch input pin D
E1
1ch input pin E
SOUT2 2ch cinema surround or SEQ setting pin
SQI2 2ch cinema surround or SEQ setting pin
SOUT1 1ch cinema surround or SEQ setting pin
SQI1 1ch cinema surround or SEQ setting pin
E2
2ch input pin E
FILTER 1/2 VCC pin
GND Ground pin
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© 2010 ROHM Co., Ltd. All rights reserved.
2010.10 - Rev.A
8/15
Technical Note
BD3870FS,BD3871FS,BD3872FS,BD3873FS
●Description of operations
1)Bass filter
Using external components, center frequencies and Q factors of the bass characteristics are flexible
1
f0
(Hz)
R1R2 R3 R4 C1C2
2π
R2 R3 R4
IN
+
-
R1R2R4C1C2
R3
R4
R2 R3 R4
Q
R1 C1 C2
R2
R2 R3 R4
C2
C1
C2
C1
C1
C2
1
1
R1 R2 R3 R4
R1
G(boost) 20log
(dB)
R2R3
R1 R2 R3 R4
Fig.5
R2R3
C2
1
R1
R2 R3 R4
R2(R3 R4
C1
C2
Gcut 20log
(dB)
ٛ
ٛ
ٛ
ٛ
1
R1
R2 R3 R4
C1
Standard values of R3, R4 (reference)
(R1=5.6kΩ, R2=390kΩ, C1=C2=0.1µF)
G
Resistance (kΩ) * Typ.
Bass Boost Cut Amount
R3
R4
0dB
2dB
77.64
58.90
44.02
32.20
22.82
15.36
9.44
0
G
G
18.73
33.60
45.42
54.80
62.26
68.18
72.84
4dB
6dB
f
F0
8dB
10dB
12dB
14dB
4.78
* The actual boost cut amount may deviate from the standard values in some degree.
Fig.6
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© 2010 ROHM Co., Ltd. All rights reserved.
2010.10 - Rev.A
9/15
Technical Note
BD3870FS,BD3871FS,BD3872FS,BD3873FS
2)Treble filter
IN
1
OUT
+
-
fc =
(Hz)
R1+R2+Zc
2πR2C
G (boost) = 20log
(dB)
R2+Zc
R2+Zc
R1+R2+Zc
R1
R2
C
G (cut) = 20log
(dB)
1
Zc =
(Ω)
jωc
Fig.7
Standard values of R1, R2 (reference)
G
Resistance (kΩ) * Typ.
3dB
Treble Boost Cut Amount
R1
R2
0dB
0
36.28
28.82
22.89
18.18
14.44
11.47
G
G
2dB
7.46
4dB
13.39
18.10
21.84
24.81
27.20
29.04
f
fc
6dB
8dB
10dB
3dB
12dB
9.08
7.24
14dB (BD3872FS only)
* The actual boost cut amount may deviate from the standard values in some degree.
Fig.8
3)Matrix surround
IN1
OUT1
+
+
L
+
(4.14L/2 - 2.14R/2)
× 1/2
× 1/2
×2.14
Fig.9
+
-
+
(4.14R/2- 2.14L/2)
OUT2
-
+
R
+
IN2
Matrix surround is constructed as shown above. Gains are defined as follows:
In-phase Gain: Gains obtained on OUT1 and OUT2 against IN1 when inputting a signal of the equivalent level and
in-phase (L=R) to IN1 and IN2.
OUT1
OUT2
4.14
2.14
20log1 0
(dB)
L
L
L 1
IN1
IN2
2
2
Single-phase Gain: Gains obtained on OUT1 and OUT2 against IN1 when inputting a signal to IN1 and AC-grounding IN2
(R=0).
OUT1 4.14
L
L
2,07
20log2.07 6.3
(dB)
(dB)
IN1
2
OUT2
2.14
20log 1.07 0.59
L
L
1.07
IN1
2
Opposite-phase Gain: Gains obtained on OUT1 and OUT2 against IN1 when inputting signals of the equivalent level and
opposite-phase (L-R) to IN1 and IN2.
OUT1 OUT2
4.14
2.14
20log3.14 10 (dB)
L
L
L 3.14
IN1
IN2
2
2
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2010.10 - Rev.A
10/15
© 2010 ROHM Co., Ltd. All rights reserved.
Technical Note
BD3870FS,BD3871FS,BD3872FS,BD3873FS
1)Sound generation using Loud Speaker Equalizer (BD3872FS)
Using external components, one of the following two functions can be established; one having an effect to localize the
vocal forward and enhance it (Loud Speaker Equalizer) and the other having an effect to clarify the vocal quality and
improve the Articulation Index (Cinema Surround). Those characteristic values can be adjusted by choosing the external
components with desirable constants. Details of above two functions are described below:
◎Cinema Surround
Constructing the external components as shown below allows the vocals to be moved forward and enhanced.
Surround effect with enhanced vocal is achieved by turning on the built-in surround simultaneously.
Merging this effect, while playing movies on a DVD player, will make vocal listening clearer and surround effect
more impactful.
31
30
29
32
Loud speaker
equalizer1
Loud speaker
equalizer2
Fig.10
◎Loud Speaker Equalizer (SEQ)
BOOM BOX and Micro-sound systems are often restricted to using small-diameter speakers because of location space.
These speakers, where the vocal range are attenuated, may give an impression of having a muffled vocal sound
with respect to its audibility. Using the Loud Speaker Equalizer, the vocal quality which degrades in small-diameter
speakers, can be improved and the Articulation Index is also increased.
OUT
IN
Phase Shifter
HPF
SOUT (29. 31pin)
SEQ (30, 32pin)
C2
C1
Fig.11
・C1 can be selected to determine the frequency where the phase should be inverted.
C1
Larger value
Smaller value
Frequency where the phase is inverted
Set to the lower frequency side
Set to the higher frequency side
・C2 can be selected to determine the HPF cut-off frequency fc. The SEQ gain remains constant.
1
fc =
(Hz)
2RC
(Where R is a built-in resistance of 10kΩ)
G=5dB
(Constant)
3dB
Fc
FREQUENCY
Fig.12
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© 2010 ROHM Co., Ltd. All rights reserved.
2010.10 - Rev.A
11/15
Technical Note
BD3870FS,BD3871FS,BD3872FS,BD3873FS
●Reference data
10
1
10
8
10
1
6
0.1
0.1
4
0.01
0.001
0.01
0.001
2
0
0.001
0.01
0.1
1
10
0.001
0.01
0.1
1
10
0
2
4
6
8
10
INPUT VOLTAGE (Vrms)
INPUT VOLTAGE (Vrms)
VCC (V)
Fig.13 Circuit Current - Power Supply
Voltage
Fig.14 Output Voltage - Input Voltage
(BD3870FS)
Fig.15 Total Harmonic Distortion
ratio - Input Voltage (BD3870FS)
20
30
15
+14dB
At 24dB setting
At 18dB setting
25
10
18
20
15
10
5
5
0
-14～+14dB
2dB step
16
14
12
10
-5
-10
-15
-14dB
0
10
100
1000
10000 100000
10
100
1000
10000 100000
10
100
1000
10000 100000
FREQUENCY (Hz)
FREQUENCY (Hz)
FREQUENCY (Hz)
Fig.16 Current Gain - Frequency
(BD3870FS, BD3873FS)
Fig.17 Voltage Gain - Frequency
(BD3871FS)
Fig.18 Bass Gain - Frequency
20
15
15
+12dB
+14dB
10
10
15
-12～+12dB
2dB step
At oppoite-phase input
5
5
0
10
5
0
-5
-5
-10
-10
-12dB
-14dB
0
-15
-15
10
100
1000
10000 100000
10
100
1000
10000 100000
10
100
1000
10000 100000
FREQUENCY (Hz)
FREQUENCY (Hz)
FREQUENCY (Hz)
Fig.19 Treble Gain - Frequency
(BD3870FS,BD3871FS,BD3873FS)
Fig.20 Treble Gain - Frequency
(BD3872FS)
Fig.21 Surround Gain - Frequency
10
8
6
4
2
0
10
100
1000
10000 100000
FREQUENCY (Hz)
Fig. 22 Treble Gain - Frequency
(BD3872FS)
www.rohm.com
2010.10 - Rev.A
12/15
© 2010 ROHM Co., Ltd. All rights reserved.
Technical Note
BD3870FS,BD3871FS,BD3872FS,BD3873FS
●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 electromagnetic field
Using the ICs in a strong electromagnetic field can cause operation malfunction.
8) Power-ON RESET
A built-in circuit for performing initialization inside the IC at power-ON is provided. In unstable systems it is recommended
that the data shall be sent to all the addresses during power-ON, until this operation cycle is completed. Mute should be
applied during this cycle.
Function
Initial Condition
Input A
0dB
Input Selector
Input Gain
OFF
Loud Speaker Equalizer (BD3872FS only)
-dB
Volume
OFF
Surround
Treble Gain
Bass Gain
0dB
0dB
9) 2-wire serial control
For the CL and DA terminals, the patterned and other wirings should be routed as not to cause interference with the
analog-signal-related lines.
10) Switching between functions
Shock sound is absorbed when switching between the volume, bass, and treble functions.
11) Input coupling capacitor
As described in the figure below, low frequency characteristics are determined depending on the external capacitor value
for input coupling, and the input impedance value inside the IC.
G
C
0
A (f)
R
f
(2πfCR)2
=
A(f)
1+(2πfCR)2
Fig.23
Fig.24
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© 2010 ROHM Co., Ltd. All rights reserved.
2010.10 - Rev.A
13/15
Technical Note
BD3870FS,BD3871FS,BD3872FS,BD3873FS
12) Switching noise
For Surround and Loud Speaker Equalizer (BD3872FS only), external capacitor C is attached to the CAP pin as a measures
to control the switching noise. In the application circuit, a constant value as an example, is indicated by the CAP pin.
The time constant, which is used to charge/discharge the external capacitor C (varying between Vbe to 5Vbe (2.65V)) on
the CAP pin, controls the soft switching operation. The switching time constant T is stated as T=2.55×105×C.
Vbe has a temperature characteristic and may affect the time constant T.
13) Input Selector and Input Gain
When setting/changing Input Selector or Input Gain, the soft switching operation does not function and therefore noise is
not controlled. For this reason, it is recommended to provide a mute circuit constructed of the external components for the
set design.
MUTE setting example
MUTE
(L=ON, H=OFF)
SERIAL DATA
SERIAL DATA
500～600ms
40～60ms
INPUT SOURCE
Fig.25
●Thermal Derating Curve
1200
SSOP-A32
1000
SSOP-A24
800
600
400
200
0
0
25
50
75
100
125
Ambient Temperature: Ta(℃)
When installed ROHM standard board
(70×70×1.6mm Glass epoxy board)
Fig.26
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© 2010 ROHM Co., Ltd. All rights reserved.
2010.10 - Rev.A
14/15
Technical Note
BD3870FS,BD3871FS,BD3872FS,BD3873FS
●Ordering part number
B
D
3
8
7
0
F
S
-
E
2
Part No.
Part No.
3870,3871,3873
3872
Package
FS: SSOP-A24
SSOP-A32
Packaging and forming specification
E2: Embossed tape and reel
SSOP-A24
<Tape and Reel information>
+6°
10 0.2
(MAX 10.35 include BURR)
4°
−4°
Tape
Embossed carrier tape
2000pcs
24
13
Quantity
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
(
)
1
12
+0.1
−0.05
0.17
0.1
Direction of feed
1pin
0.38 0.1
0.8
Reel
Order quantity needs to be multiple of the minimum quantity.
(Unit : mm)
∗
SSOP-A32
<Tape and Reel information>
13.6 0.2
(MAX 13.95 include BURR)
Tape
Embossed carrier tape
Quantity
2000pcs
32
17
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
(
)
1
16
0.15 0.1
0.36 0.1
0.1
0.8
Direction of feed
1pin
Reel
(Unit : mm)
Order quantity needs to be multiple of the minimum quantity.
∗
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© 2010 ROHM Co., Ltd. All rights reserved.
2010.10 - Rev.A
15/15
Notice
N o t e s
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, commu-
nication 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
scope or not in accordance with the instruction manual.
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
instrument, transportation equipment, aerospace machinery, nuclear-reactor controller, fuel-
controller or other safety device). ROHM shall bear no responsibility in any way for use of any
of the Products for the above special purposes. If a Product is intended to be used for any
such special purpose, please contact a ROHM sales representative before purchasing.
If you intend to export or ship overseas any Product or technology specified herein that may
be controlled under the Foreign Exchange and the Foreign Trade Law, you will be required to
obtain a license or permit under the Law.
Thank you for your accessing to ROHM product informations.
More detail product informations and catalogs are available, please contact us.
ROHM Customer Support System
http://www.rohm.com/contact/
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© 2010 ROHM Co., Ltd. All rights reserved.
R1010
A
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