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
Input Gain
BD3870FS
BD3871FS
BD3873FS
BD3872FS
0, 6, 12, 18dB
24, 26, 28dB
18, 21, 24, 27dB
0, 5, 10, 19, 21,
23, 26, 28dB
No
No
No
Yes
Three inputs
Three inputs
Three inputs
Five inputs
0 to -87dB/
1dB step, -dB
2 band
(Bass, Treble)
0 to -87dB/
1dB step, -dB
2 band
(Bass, Treble)
0 to –87dB/
1dB step, -dB
2 band
(Bass, Treble)
0 to -87dB/
1dB step, -dB
2 band
(Bass, Treble)
Yes
Yes
Yes
Yes
Two-wire serial
Two-wire serial
Two-wire serial
Two-wire serial
SSOP-A24
SSOP-A24
SSOP-A24
SSOP-A32
Loud Speaker Equalizer (SEQ)
Input Selector
Volume
Equalizer
Surround
Serial Control
Package
●Absolute maximum ratings (Ta=25℃)
Prameter
Symbol
Ratings
BD3870FS
BD3871FS
BD3873FS
BD3872FS
Unit
Power Supply Voltage
Vcc
10
10
10
10
V
Power Dissipation
Pd
800 *1
800 *1
800 *1
950 *2
mW
Operating Temperature Range
Topr
-25 to +75
-25 to +75
-25 to +75
-25 to +75
℃
Storage Temperature Range
Tstg
-55 to +125
-55 to +125
-55 to +125
-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
Prameter
Operating Voltage Range
Symbol
Vcc
Ratings
BD3870FS
BD3871FS
BD3873FS
BD3872FS
4.5 to 9.5
4.5 to 9.5
4.5 to 9.5
4.5 to 9.5
Unit
V
*It must function normally at Ta=25℃.
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© 2010 ROHM Co., Ltd. All rights reserved.
1/15
2010.10 - Rev.A
Technical Note
BD3870FS,BD3871FS,BD3872FS,BD3873FS
Block
●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)
Parameter
Circuit Current
Bass
Volume
Total
Total Output Voltage Gain
Treble
Surround
IQ
Gv
Limits
Min.
Typ.
Max.
-
8
21
-2
0
2
22
24
26
16
18
20
Unit
At no signal
dB
BD3870FS, BD3872FS
Gv=20log(VOUT/VIN)
BD3871FS
Gv=20log(VOUT/VIN)
BD3873FS
Gv=20log(VOUT/VIN)
BW=400 to 30kHz
THD
-
0.01
0.1
%
Maximum Output Voltage
Vom
1.6
2.1
-
Vrms
-
4.5
15
Total Output Noise Voltage
Vno
-
40
80
µVrms
Total Residual Noise Voltage
Vmno
-
4.5
15
µVrms
Cross-talk between Channels
CTC
-
-80
-70
dB
Cross-talk between Selectors
CTS
-
-80
-70
dB
35
50
65
Input Impedance
Rin
70
100
130
Condition
mA
Total Harmonic Distortion ratio
THD=1%
BW=400 to 30kHz
BD3870FS, BD3872FS
Rg=0Ω, BW=IHF-A
BD3871FS, BD3873FS
Rg=0Ω, BW=IHF-A
Rg=0Ω, BW=IHF-A
Volume=-dB
Rg=0Ω, BW=IHF-A
VOUT=1Vrms
Rg=0Ω, BW=IHF-A
BD3870FS, BD3871FS, BD3873FS
kΩ
BD3872FS
Output Impedance
Rout
-
-
50
Ω
Volume Control Range
VRI
-90
-87
-84
dB
VR=20log(VOUT/VIN)
Maximum Volume Attenuation
Vmin
-
-
-90
dB
BW=IHF-A
Volume Input Impedance
Rvin
39
56
73
kΩ
Bass Boost Gain
GBB
12
14
16
dB
GB=20log(VOUT/VIN)
Bass Cut Gain
GBC
-16
-14
-12
dB
GB=20log(VOUT/VIN)
BR
-
2
-
dB
10
12
14
Bass Step Resolution
SEQ
Symbol
Treble Boost Gain
GTB
Treble Cut Gain
GTC
12
14
16
-14
-12
-10
-16
-14
-12
BD3870FS, BD3871FS, BD3873FS
dB
BD3872FS
BD3870FS, BD3871FS, BD3873FS
dB
BD3872FS
Treble Step Resolution
TR
-
2
-
dB
Surround In-phase Gain
Vsur1
-2
0
2
dB
2ch in-phase inputs
Surround Single-phase Gain
Vsur2
4.3
6.3
8.3
dB
1ch input, 1ch grounded
Surround Opposite-phase Gain
Vsur3
8
10
12
dB
2ch opposite-phase inputs
Seq
3
5
7
dB
f=10kHz
Loud Speaker Equalizer Gain
(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.
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© 2010 ROHM Co., Ltd. All rights reserved.
2/15
2010.10 - Rev.A
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
SC
(CLOCK)
90%
tsu
90%
twc
10%
thd
SI
DATA
LATCH
90%
twd
ts
th
90%
DATA
90%
90%
10%
10%
twc
tsd
ts1
90%
twh
th1
90%
DATA
10%
10%
thd
10%
LATCH
End with Low
Fig.1
Parameter
Symbol
90%
tw1
Limits
Min.
Typ.
Max.
Unit
Minimum Clock Width
Twc
2.0
-
-
µs
Minimum Data Width
twd
2.0
-
-
µs
Minimum Latch Width
Tw1
2.0
-
-
µs
Data Set-up Time (DATACLK)
Tsd
1.0
-
-
µs
Data Hold Time (CLKDATA)
Thd
1.0
-
-
µs
Latch Set-up Time (CLKLATCH)
Ts1
1.0
-
-
µs
Latch Hold Time (DATALATCH)
Th1
1.0
-
-
µs
Latch Low Set-up Time
Ts
1.0
-
-
µs
Latch Low Hold Width
Twh
2.0
-
-
µs
2) Voltage Conditions for Control Signals
Limits
Parameter
Min.
Typ.
Max.
(≦Vcc)
Unit
“H” Input Voltage
2.2
-
5.5
V
Vcc=4.5 to 9.5V
“L” Input Voltage
0
-
1.0
V
Vcc=4.5 to 9.5V
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© 2010 ROHM Co., Ltd. All rights reserved.
3/15
Condition
2010.10 - Rev.A
Technical Note
BD3870FS,BD3871FS,BD3872FS,BD3873FS
3) Control Data Format List
Basic Configuration of Control Data Format
Data input direction
MSB
D9
D8
D7
LSB
D6
D5
D4
D3
D2
D1
Select
Address
Data
Control Data Format (BD3870FS, BD3871FS, BD3873FS)
Data input direction
D9
D8
D7
D6
D5
(1)
Input Selector
Input Gain
(2)
Surround
D4
D3
D2
D1
D0
*
*
*
0
0
*
0
1
1
0
Volume A
(3)
Volume B
Bass Gain
(4)
*
*
Control Data Format (BD3872FS)
Data input direction
D9
D8
(1)
Treble Gain
*
*
*
*
*
*
1
1
D7
D6
D5
D4
D3
D2
D1
D0
*
*
0
0
*
0
1
1
0
1
1
Input Gain
(2)
Input Selector
Volume A
(3)
Volume B
Bass Gain
(4)
*
*
D0
*
Treble Gain
*
*
*
Surround
SEQ
・”*” 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
L
Data(2)
LSB
L
MSB
Data(3)
LSB
L
MSB
Data(4)
LSB
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.
4/15
2010.10 - Rev.A
Technical Note
BD3870FS,BD3871FS,BD3872FS,BD3873FS
●Block diagram, application circuit, pin assignment (BD3870FS, BD3871FS, BD3873FS)
5.6k
5.6k
0.1μ
0.1μ
0.1μ
0.1μ
OUT1 OUT2
0.33μ 0.0022μ 0.0022μ
10μ
390k
24
Surround
23
22
Treble1
fc=8k Hz
Treble2
fc=8kHz
21
DATA
VCC LATCH CLOCK
10μ
390k
20
19
Bass2
f0 =80Hz
18
17
16
15
14
13
Logic
Bass1
f0=80Hz
Vcc/2
Vcc/2
0dB
~
-87dB
-∞
Vcc/2
Vcc/2
Vcc/2
1
2
50k
3
4
5
50k
50k
6
7
50k
50k
8
50k
9
10
11
12
47μ
10μ
10μ
A1
10μ
10μ
A2
B1
10μ
10μ
10μ
4.7k
B2
4.7k
10μ
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
VIN1
1ch volume input pin
13
SC
Serial clock input pin
2
VIN2
2ch volume input pin
14
SI
Serial data input pin
3
SEL2
2ch input selector output pin
15
VCC
Power supply pin
4
SEL1
1ch input selector output pin
16
OUT2
2ch output pin
5
A1
1ch input pin A
17
OUT1
1ch output pin
6
A2
2ch input pin A
18
BOUT1
1ch bass filter setting pin
7
B1
1ch input pin B
19
BNF1
1ch bass filter setting pin
8
B2
2ch input pin B
20
BOUT2
2ch bass filter setting pin
9
C1
1ch input pin C
21
BNF2
2ch bass filter setting pin
10
C2
2ch input pin C
22
TNF2
2ch treble filter setting pin
11
FILTER
1/2 VCC pin
23
TNF1
1ch treble filter setting pin
12
GND
Ground pin
24
CAP
Time constant setting pin for absorbing
surround switching shock sound
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© 2010 ROHM Co., Ltd. All rights reserved.
5/15
2010.10 - Rev.A
Technical Note
BD3870FS,BD3871FS,BD3872FS,BD3873FS
●Block diagram, application circuit, pin assignment (BD3872FS)
OUT1
0.001μ
0.022μ
Vcc/2
32
31
Loud speaker
equalizer2
5.6K
0.1μ
4.7μ
4.7μ
27
26
Treble1
fc=10kHz
Treble2
fc=10kHz
DATA CLOCK
LATCH
0.33μ
+
390K
390K
28
29
0.1μ
+
Vcc/2
30
5.6K
0.1μ
25
24
Bass1
f 0=80Hz
23
22
21
20
19
18
17
Logic
Bass2
f0 =80Hz
Surround
Loud
speaker
0.0022μ 0.0022μ
0.1μ
0.001μ
62K
Vcc
OUT2
Vcc/2
Vcc/2
Vcc/2
0dB
~
-87dB
-∞
0dB
~
-87dB
-∞
Vcc/2
Vcc/2
100k
1
2
3
4
100k
5
6
100k
100k
8
7
100k
9
100k
10
100k
100k
12
11
100k
13
100k
14
15
16
+
0.1μ
0.22μ
0.1μ
0.1μ
0.1μ
0.1μ
0.1μ
0.1μ
0.1μ
0.22μ
A1
A2
B1
B2
C1
C2
D1
D2
E1
0.1μ
0.1μ
4.7k
4.7k
10μ
E2
Unit: Resistance =Ω, Capacitor = F
Fig.3 Application to Cinema Surround
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© 2010 ROHM Co., Ltd. All rights reserved.
6/15
2010.10 - Rev.A
Technical Note
BD3870FS,BD3871FS,BD3872FS,BD3873FS
OUT1 OUT2
0.33μ
0.01μ
0.33μ
0.01μ
0.0022μ
0.0022μ
0.1μ
5.6K
0.1μ
0.1μ
5.6K
0.1μ
4.7μ
+
32
31
29
Loud speaker
equalizer2
28
27
Treble1
fc=10kHz
Treble2
fc=10kHz
Bass1
f0 =80Hz
390K
23
24
4.7μ
DATA CLOCK
LATCH
0.33μ
+
22
21
20
19
18
17
Logic
Bass2
f0 =80Hz
Surround
Loud speaker
equalizer1
30
390K
26
25
Vcc
Vcc/2
Vcc/2
Vcc/2
0dB
~
-87dB
-∞
0dB
~
-87dB
-∞
Vcc/2
Vcc/2
100k
1
2
3
4
5
100k
6
100k
100k
8
7
100k
9
100k
10
100k
11
100k
12
100k
13
100k
14
15
16
+
0.1μ
0.22μ
0.1μ
0.1μ
0.1μ
0.1μ
0.1μ
0.1μ
0.1μ
0.22μ
A1
A2
B1
B2
C1
C2
D1
D2
E1
0.1μ
0.1μ
4.7k
4.7k
10μ
E2
Unit: Resistance =Ω, Capacitor = F
Fig.4 Application to Loud Speaker Equalizer
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© 2010 ROHM Co., Ltd. All rights reserved.
7/15
2010.10 - Rev.A
Technical Note
BD3870FS,BD3871FS,BD3872FS,BD3873FS
●Pin description (BD3872FS)
Pin No. Pin Name
Description
Pin No. Pin Name
Description
1
VIN1
1ch volume input pin
17
SC
Serial clock input pin
2
SEL1
1ch input selector output pin
18
SI
Serial data input pin
3
VIN2
2ch volume input pin
19
VCC
Power supply pin
4
SEL2
2ch input selector output pin
20
CAP
Time constant setting pin for absorbing
switching shock sound
5
A1
1ch input pin A
21
OUT2
2ch output pin
6
A2
2ch input pin A
22
OUT1
1ch output pin
7
B1
1ch input pin B
23
BOUT2
2ch bass filter setting pin
8
B2
2ch input pin B
24
BNF2
2ch bass filter setting pin
9
C1
1ch input pin C
25
BOUT1
1ch bass filter setting pin
10
C2
2ch input pin C
26
BNF1
1ch bass filter setting pin
11
D1
1ch input pin D
27
TNF2
2ch treble filter setting pin
12
D2
2ch input pin D
28
TNF1
1ch treble filter setting pin
13
E1
1ch input pin E
29
SOUT2
2ch cinema surround or SEQ setting pin
14
E2
2ch input pin E
30
SQI2
2ch cinema surround or SEQ setting pin
15
FILTER
1/2 VCC pin
31
SOUT1
1ch cinema surround or SEQ setting pin
16
GND
Ground pin
32
SQI1
1ch cinema surround or SEQ setting pin
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© 2010 ROHM Co., Ltd. All rights reserved.
8/15
2010.10 - Rev.A
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)
R1R2R3 R4 C1C2
2π
IN
R2 R3 R4
+
R3
R1R2R4C1C2
R4
Q
R2 R3 R4
R1C1 C2
R2
C1
R2 R3 R4
C2
R1
G(boost) 20log
R1R2 R3 R4
R2R3
R1R2 R3 R4
Fig.5
R2R3
R1R2 R3 R4
Gٛcut ٛ 20log
R2(R3 R4 ٛ
R1R2 R3 R4
Standard values of R3, R4 (reference)
(R1=5.6kΩ, R2=390kΩ, C1=C2=0.1µF)
Resistance (kΩ) * Typ.
Bass Boost Cut Amount
R3
R4
0dB
77.64
0
2dB
58.90
18.73
4dB
44.02
33.60
6dB
32.20
45.42
8dB
22.82
54.80
10dB
15.36
62.26
12dB
9.44
68.18
14dB
4.78
72.84
C2
C1
C2
C1
C2
C1
C2
C1
1
(dB)
1
1
ٛ(dB)
1
G
G
f
F0
G
* 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.
9/15
2010.10 - Rev.A
Technical Note
BD3870FS,BD3871FS,BD3872FS,BD3873FS
2) Treble filter
IN
OUT
+
fc =
-
1
(Hz)
2πR2C
G (boost) = 20log
R1
R2
G (cut) = 20log
Zc =
1
jωc
R1+R2+Zc
(dB)
R2+Zc
R2+Zc
(dB)
R1+R2+Zc
(Ω)
C
Fig.7
G
Standard values of R1, R2 (reference)
Resistance (kΩ) * Typ.
Treble Boost Cut Amount
R1
R2
0dB
0
36.28
2dB
7.46
28.82
4dB
13.39
22.89
6dB
18.10
18.18
8dB
21.84
14.44
10dB
24.81
11.47
12dB
27.20
14dB (BD3872FS only)
29.04
9.08
7.24
3dB
G
G
3dB
Fig.8
* The actual boost cut amount may deviate from the standard values in some degree.
3) Matrix surround
f
fc
IN1
+
L
OUT1
+
+
(4.14L/2 - 2.14R/2)
× 1/2
+
+ -
× 2.14
× 1/2
R
IN2
Fig.9
+
+
-
(4.14R/2 - 2.14L/2)
OUT2
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
2
IN1
IN2
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)
IN1
2
OUT2
2.14
20log 1.07 0.59 (dB)
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 ROHM Co., Ltd. All rights reserved.
10/15
2010.10 - Rev.A
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.
32
31
Loud speaker
equalizer1
30
29
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.
IN
OUT
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
Frequency where the phase is inverted
Larger value
Set to the lower frequency side
Smaller value
Set to the higher frequency side
・C2 can be selected to determine the HPF cut-off frequency fc. The SEQ gain remains constant.
1
2RC
(Hz)
GAIN
fc =
(Where R is a built-in resistance of 10kΩ)
3dB
Fc
G=5dB
(Constant)
FREQUENCY
Fig.12
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© 2010 ROHM Co., Ltd. All rights reserved.
11/15
2010.10 - Rev.A
Technical Note
BD3870FS,BD3871FS,BD3872FS,BD3873FS
●Reference data
ICC (mA)
8
6
4
2
2
4
6
8
10
1
1
0.1
10
0.01
0.1
1
10
0.001
0.001
0.01
10
Fig.15 Total Harmonic Distortion
ratio - Input Voltage (BD3870FS)
30
15
+14dB
At 24dB setting
12
25
10
20
5
GAIN (dB)
GAIN (dB)
18
14
1
Fig.14 Output Voltage - Input Voltage
(BD3870FS)
At 18dB setting
16
0.1
INPUT VOLTAGE (Vrms)
20
GAIN (dB)
0.01
INPUT VOLTAGE (Vrms)
VCC (V)
Fig.13 Circuit Current - Power Supply
Voltage
0.1
0.01
0.001
0.001
0
0
10
THD+N (%)
OUTPUT VOLTAGE (Vrms)
10
15
10
5
-14~+14dB
2dB step
0
-5
-10
-14dB
0
10
10
100
1000
10000
-15
10
100000
Fig.16 Current Gain - Frequency
(BD3870FS, BD3873FS)
10000
100000
10
15
+12dB
100
1000
10000
100000
FREQUENCY (Hz)
Fig.17 Voltage Gain - Frequency
(BD3871FS)
10
Fig.18 Bass Gain - Frequency
20
+14dB
10
5
0
-5
15
-14~+14dB
5
GAIN (dB)
-12~+12dB
2dB step
GAIN (dB)
GAIN (dB)
1000
FREQUENCY (Hz)
FREQUENCY (Hz)
15
100
2dB step
0
-5
At oppoite-phase input
10
5
-10
-10
-12dB
-15
10
100
1000
10000
100000
FREQUENCY (Hz)
-14dB
-15
10
100
1000
10000
0
100000
FREQUENCY (Hz)
Fig.19 Treble Gain - Frequency
(BD3870FS,BD3871FS,BD3873FS)
Fig.20 Treble Gain - Frequency
(BD3872FS)
10
100
1000
10000
100000
FREQUENCY (Hz)
Fig.21 Surround Gain - Frequency
10
GAIN (dB)
8
6
4
2
0
10
100
1000
10000
100000
FREQUENCY (Hz)
Fig. 22 Treble Gain - Frequency
(BD3872FS)
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© 2010 ROHM Co., Ltd. All rights reserved.
12/15
2010.10 - Rev.A
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
Input Selector
0dB
Input Gain
Loud Speaker Equalizer
OFF
(BD3872FS only)
Volume
-dB
Surround
OFF
Treble Gain
0dB
Bass Gain
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)
A(f) =
Fig.23
www.rohm.com
© 2010 ROHM Co., Ltd. All rights reserved.
2
1+(2πfCR)2
Fig.24
13/15
2010.10 - Rev.A
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
Power Dissipation : Pd (mW)
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.
14/15
2010.10 - Rev.A
Technical Note
BD3870FS,BD3871FS,BD3872FS,BD3873FS
●Ordering part number
B
D
3
Part No.
8
7
0
F
S
-
Package
FS: SSOP-A24
SSOP-A32
Part No.
3870,3871,3873
3872
E
2
Packaging and forming specification
E2: Embossed tape and reel
SSOP-A24
10 ± 0.2
(MAX 10.35 include BURR)
0.5±0.2
12
Tape
Embossed carrier tape
Quantity
2000pcs
0.1±0.1
0.8
0.1
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
)
+0.1
0.17 −0.05
1.8±0.1
1
1.2±0.15
7.8±0.3
13
5.4±0.2
24
+6°
4° −4°
1pin
0.38±0.1
Reel
(Unit : mm)
Direction of feed
∗ Order quantity needs to be multiple of the minimum quantity.
SSOP-A32
13.6 ± 0.2
(MAX 13.95 include BURR)
17
Tape
Embossed carrier tape
Quantity
2000pcs
Direction
of feed
0.3MIN
5.4±0.2
7.8±0.3
32
1
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
)
16
0.11
1.8±0.1
0.15 ± 0.1
0.36 ± 0.1
0.1
0.8
1pin
Reel
(Unit : mm)
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© 2010 ROHM Co., Ltd. All rights reserved.
15/15
Direction of feed
∗ Order quantity needs to be multiple of the minimum quantity.
2010.10 - Rev.A
Datasheet
Notice
Precaution on using ROHM Products
1.
Our Products are designed and manufactured for application in ordinary electronic equipments (such as AV equipment,
OA equipment, telecommunication equipment, home electronic appliances, amusement equipment, etc.). If you
(Note 1)
, transport
intend to use our Products in devices requiring extremely high reliability (such as medical equipment
equipment, traffic equipment, aircraft/spacecraft, nuclear power controllers, fuel controllers, car equipment including car
accessories, safety devices, etc.) and whose malfunction or failure may cause loss of human life, bodily injury or
serious damage to property (“Specific Applications”), please consult with the ROHM sales representative in advance.
Unless otherwise agreed in writing by ROHM in advance, ROHM shall not be in any way responsible or liable for any
damages, expenses or losses incurred by you or third parties arising from the use of any ROHM’s Products for Specific
Applications.
(Note1) Medical Equipment Classification of the Specific Applications
JAPAN
USA
EU
CHINA
CLASSⅢ
CLASSⅡb
CLASSⅢ
CLASSⅢ
CLASSⅣ
CLASSⅢ
2.
ROHM designs and manufactures its Products subject to strict quality control system. However, semiconductor
products can fail or malfunction at a certain rate. Please be sure to implement, at your own responsibilities, adequate
safety measures including but not limited to fail-safe design against the physical injury, damage to any property, which
a failure or malfunction of our Products may cause. The following are examples of safety measures:
[a] Installation of protection circuits or other protective devices to improve system safety
[b] Installation of redundant circuits to reduce the impact of single or multiple circuit failure
3.
Our Products are designed and manufactured for use under standard conditions and not under any special or
extraordinary environments or conditions, as exemplified below. Accordingly, ROHM shall not be in any way
responsible or liable for any damages, expenses or losses arising from the use of any ROHM’s Products under any
special or extraordinary environments or conditions. If you intend to use our Products under any special or
extraordinary environments or conditions (as exemplified below), your independent verification and confirmation of
product performance, reliability, etc, prior to use, must be necessary:
[a] Use of our Products in any types of liquid, including water, oils, chemicals, and organic solvents
[b] Use of our Products outdoors or in places where the Products are exposed to direct sunlight or dust
[c] Use of our Products in places where the Products are exposed to sea wind or corrosive gases, including Cl2,
H2S, NH3, SO2, and NO2
[d] Use of our Products in places where the Products are exposed to static electricity or electromagnetic waves
[e] Use of our Products in proximity to heat-producing components, plastic cords, or other flammable items
[f] Sealing or coating our Products with resin or other coating materials
[g] Use of our Products without cleaning residue of flux (even if you use no-clean type fluxes, cleaning residue of
flux is recommended); or Washing our Products by using water or water-soluble cleaning agents for cleaning
residue after soldering
[h] Use of the Products in places subject to dew condensation
4.
The Products are not subject to radiation-proof design.
5.
Please verify and confirm characteristics of the final or mounted products in using the Products.
6.
In particular, if a transient load (a large amount of load applied in a short period of time, such as pulse. is applied,
confirmation of performance characteristics after on-board mounting is strongly recommended. Avoid applying power
exceeding normal rated power; exceeding the power rating under steady-state loading condition may negatively affect
product performance and reliability.
7.
De-rate Power Dissipation (Pd) depending on Ambient temperature (Ta). When used in sealed area, confirm the actual
ambient temperature.
8.
Confirm that operation temperature is within the specified range described in the product specification.
9.
ROHM shall not be in any way responsible or liable for failure induced under deviant condition from what is defined in
this document.
Precaution for Mounting / Circuit board design
1.
When a highly active halogenous (chlorine, bromine, etc.) flux is used, the residue of flux may negatively affect product
performance and reliability.
2.
In principle, the reflow soldering method must be used; if flow soldering method is preferred, please consult with the
ROHM representative in advance.
For details, please refer to ROHM Mounting specification
Notice - GE
© 2014 ROHM Co., Ltd. All rights reserved.
Rev.002
Datasheet
Precautions Regarding Application Examples and External Circuits
1.
If change is made to the constant of an external circuit, please allow a sufficient margin considering variations of the
characteristics of the Products and external components, including transient characteristics, as well as static
characteristics.
2.
You agree that application notes, reference designs, and associated data and information contained in this document
are presented only as guidance for Products use. Therefore, in case you use such information, you are solely
responsible for it and you must exercise your own independent verification and judgment in the use of such information
contained in this document. ROHM shall not be in any way responsible or liable for any damages, expenses or losses
incurred by you or third parties arising from the use of such information.
Precaution for Electrostatic
This Product is electrostatic sensitive product, which may be damaged due to electrostatic discharge. Please take proper
caution in your manufacturing process and storage so that voltage exceeding the Products maximum rating will not be
applied to Products. Please take special care under dry condition (e.g. Grounding of human body / equipment / solder iron,
isolation from charged objects, setting of Ionizer, friction prevention and temperature / humidity control).
Precaution for Storage / Transportation
1.
Product performance and soldered connections may deteriorate if the Products are stored in the places where:
[a] the Products are exposed to sea winds or corrosive gases, including Cl2, H2S, NH3, SO2, and NO2
[b] the temperature or humidity exceeds those recommended by ROHM
[c] the Products are exposed to direct sunshine or condensation
[d] the Products are exposed to high Electrostatic
2.
Even under ROHM recommended storage condition, solderability of products out of recommended storage time period
may be degraded. It is strongly recommended to confirm solderability before using Products of which storage time is
exceeding the recommended storage time period.
3.
Store / transport cartons in the correct direction, which is indicated on a carton with a symbol. Otherwise bent leads
may occur due to excessive stress applied when dropping of a carton.
4.
Use Products within the specified time after opening a humidity barrier bag. Baking is required before using Products of
which storage time is exceeding the recommended storage time period.
Precaution for Product Label
QR code printed on ROHM Products label is for ROHM’s internal use only.
Precaution for Disposition
When disposing Products please dispose them properly using an authorized industry waste company.
Precaution for Foreign Exchange and Foreign Trade act
Since our Products might fall under controlled goods prescribed by the applicable foreign exchange and foreign trade act,
please consult with ROHM representative in case of export.
Precaution Regarding Intellectual Property Rights
1.
All information and data including but not limited to application example contained in this document is for reference
only. ROHM does not warrant that foregoing information or data will not infringe any intellectual property rights or any
other rights of any third party regarding such information or data. ROHM shall not be in any way responsible or liable
for infringement of any intellectual property rights or other damages arising from use of such information or data.:
2.
No license, expressly or implied, is granted hereby under any intellectual property rights or other rights of ROHM or any
third parties with respect to the information contained in this document.
Other Precaution
1.
This document may not be reprinted or reproduced, in whole or in part, without prior written consent of ROHM.
2.
The Products may not be disassembled, converted, modified, reproduced or otherwise changed without prior written
consent of ROHM.
3.
In no event shall you use in any way whatsoever the Products and the related technical information contained in the
Products or this document for any military purposes, including but not limited to, the development of mass-destruction
weapons.
4.
The proper names of companies or products described in this document are trademarks or registered trademarks of
ROHM, its affiliated companies or third parties.
Notice - GE
© 2014 ROHM Co., Ltd. All rights reserved.
Rev.002
Datasheet
General Precaution
1. Before you use our Pro ducts, you are requested to care fully read this document and fully understand its contents.
ROHM shall n ot be in an y way responsible or liabl e for fa ilure, malfunction or acci dent arising from the use of a ny
ROHM’s Products against warning, caution or note contained in this document.
2. All information contained in this docume nt is current as of the issuing date and subj ect to change without any prior
notice. Before purchasing or using ROHM’s Products, please confirm the la test information with a ROHM sale s
representative.
3.
The information contained in this doc ument is provi ded on an “as is” basis and ROHM does not warrant that all
information contained in this document is accurate an d/or error-free. ROHM shall not be in an y way responsible or
liable for an y damages, expenses or losses incurred b y you or third parties resulting from inaccur acy or errors of or
concerning such information.
Notice – WE
© 2014 ROHM Co., Ltd. All rights reserved.
Rev.001