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ROHM Semiconductor |
Sound Processors for BOOM BOX / Mini-component Stereo
Sound Processors
with Built-in 2-band Equalizers
BD3870FS,BD3871FS,BD3872FS,BD3873FS
No.10086EAT02
●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
Loud Speaker Equalizer (SEQ)
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
Yes
Input Selector
Volume
Equalizer
Surround
Three inputs
0 to -87dB/
1dB step, -dB
2 band
(Bass, Treble)
Yes
Three inputs
0 to -87dB/
1dB step, -dB
2 band
(Bass, Treble)
Yes
Three inputs
0 to –87dB/
1dB step, -dB
2 band
(Bass, Treble)
Yes
Five inputs
0 to -87dB/
1dB step, -dB
2 band
(Bass, Treble)
Yes
Serial Control
Two-wire serial
Two-wire serial
Two-wire serial
Two-wire serial
Package
SSOP-A24
SSOP-A24
SSOP-A24
SSOP-A32
●Absolute maximum ratings (Ta=25℃)
Prameter
Symbol
BD3870FS
Ratings
BD3871FS BD3873FS
Power Supply Voltage
Power Dissipation
Vcc 10
Pd 800 *1
10
800 *1
10
800 *1
Operating Temperature Range Topr
-25 to +75
-25 to +75
-25 to +75
Storage Temperature Range
Tstg -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
*It must function normally at Ta=25℃.
Symbol
Vcc
BD3870FS
4.5 to 9.5
Ratings
BD3871FS BD3873FS
4.5 to 9.5
4.5 to 9.5
BD3872FS
10
950 *2
-25 to +75
-55 to +125
BD3872FS
4.5 to 9.5
Unit
V
mW
℃
℃
Unit
V
www.rohm.com
© 2010 ROHM Co., Ltd. All rights reserved.
1/15
2010.10 - Rev.A
BD3870FS,BD3871FS,BD3872FS,BD3873FS
Technical Note
●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
Limits
Symbol
Min. Typ. Max.
Unit
Condition
Circuit Current
IQ - 8 21 mA At no signal
Total Output Voltage Gain
-2 0 2
BD3870FS, BD3872FS
Gv=20log(VOUT/VIN)
Gv
22
24
26
dB
BD3871FS
Gv=20log(VOUT/VIN)
16 18 20
BD3873FS
Gv=20log(VOUT/VIN)
Total Harmonic Distortion ratio THD
- 0.01 0.1
% BW=400 to 30kHz
Maximum Output Voltage
Vom 1.6 2.1
-
Vrms
THD=1%
BW=400 to 30kHz
Total Output Noise Voltage
Vno
-
-
4.5
40
15
80
µVrms
BD3870FS, BD3872FS
Rg=0Ω, BW=IHF-A
BD3871FS, BD3873FS
Rg=0Ω, BW=IHF-A
Total Residual Noise Voltage
Vmno
-
4.5
15
µVrms
Rg=0Ω, BW=IHF-A
Volume=-dB
Cross-talk between Channels
CTC
-
-80 -70
dB
Rg=0Ω, BW=IHF-A
VOUT=1Vrms
Cross-talk between Selectors
CTS
-
-80 -70
dB Rg=0Ω, BW=IHF-A
Input Impedance
35 50 65
BD3870FS, BD3871FS, BD3873FS
Rin kΩ
70 100 130
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)
Bass Step Resolution
BR - 2 - dB
Treble Boost Gain
10 12 14
BD3870FS, BD3871FS, BD3873FS
GTB
dB
12 14 16
BD3872FS
Treble Cut Gain
-14 -12 -10
GTC
-16 -14 -12
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
Loud Speaker Equalizer Gain
(BD3872FS only)
Seq
3
5
7 dB f=10kHz
* 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 ROHM Co., Ltd. All rights reserved.
2/15
2010.10 - Rev.A
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