Datasheet
Sound Processor
with Built-in 3-band Equalizer
BD37524FS
General Description
BD37524FS is a sound processor with built-in 3-band
equalizer for car audio. Other features are stereo 5ch
input selector, input-gain control, main volume,
loudness, 5ch fader volume, LPF for subwoofer, level
meter. It is equipped with an “Advanced switch circuit”,
which is an original ROHM technology that reduces
various switching noise (ex. No-signal, low frequency
likes 20Hz & large signal inputs). The “Advanced
switch” makes control of microcomputer easier and can
be used for designing high quality car audio systems.
Key Specifications
Power Supply Voltage Range:
7.0V to 9.5V
Circuit Current (No Signal):
38mA(Typ)
Total Harmonic Distortion1
(FRONT,REAR):
0.001%(Typ)
Total Harmonic Distortion2
(SUBWOOFER):
0.002%(Typ)
Maximum Input Voltage:
2.3Vrms(Typ)
Cross-talk Between Selectors:
-100dB(Typ)
Volume Control Range:
+15dB to -79dB
Output Noise Voltage1
(FRONT,REAR):
3.8µVrms(Typ)
Output Noise Voltage2
(SUBWOOFER):
4.8µVrms(Typ)
1.8µVrms(Typ)
Residual Output Noise Voltage:
Operating Temperature Range:
-40°C to +85°C
Features
Reduced switching noise of input gain control,
mute, main volume, fader volume, bass, treble,
and loudness by using advanced switch circuit
Built-in differential input selector and 4
single-ended input selectors
Built-in ground isolation amplifier inputs, which is
ideal for external stereo input.
Built-in input gain controller reduces switching
noise for volume of a portable audio input.
Lesser number of external components due to
built-in 3-band equalizer filter, LPF for subwoofer,
loudness filter. This makes,it possible to control
the Q, Gv, fo of 3-band equalizer, fc of LPF, fo, and
Gv of loudness through I
2
C BUS.
A gain adjustment quantity of ±20dB with 1 dB
step gain adjustment is possible for bass, middle,
and treble.
Built-in subwoofer output terminals.
Energy-saving design resulting in low current
consumption is achieved by utilizing the Bi-CMOS
process. It has the advantage in quality over
scaling down the power heat control of the internal
regulators.
Input pins and output pins are organized and
separately laid out to keep the signal flow in one
direction which consequently, simplify pattern
layout of the set board and decrease the board
dimensions. .
It is possible to be controlled by a 3.3V / 5V I
2
C
BUS
Package
W(Typ) x D(Typ) x H(Max)
SSOP-A24
10.00mm x 7.80mm x 2.10mm
Applications
It is optimal for car audio systems. It is also suitable for
other audio equipment such as mini Compo, micro
Compo, TV etc
○Product
structure：Silicon monolithic integrated circuit
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© 2015 ROHM Co., Ltd. All rights reserved.
TSZ22111・14・001
○This
product has no designed protection against radioactive rays
1/31
TSZ02201-0C2C0E100490-1-2
16.Dec.2015 Rev.001
BD37524FS
Typical Application Circuit
BD37524FS
Pin Configuration
FIL 1
A1
A2
B1
B2
CP1
CN
2
3
4
5
6
7
TOP VIEW
24
GND
23 SDA
22 SCL
21 VCC
20
19
18
17
16
15
14
13
OUTF1
OUTF2
OUTR1
OUTR2
OUTS1
OUTS2
LOUT
MUTE
CP2 8
D1
D2
E1
E2
9
10
11
12
Pin Descriptions
Pin No.
1
2
3
4
5
6
7
8
9
10
11
12
Pin Name
FIL
A1
A2
B1
B2
CP1
CN
CP2
D1
D2
E1
E2
Description
VCC/2 terminal
A input terminal of 1ch
A input terminal of 2ch
B input terminal of 1ch
B input terminal of 2ch
C positive input terminal of 1ch
C negative input terminal
C positive input terminal of 2ch
D input terminal of 1ch
D input terminal of 2ch
E input terminal of 1ch
E input terminal of 2ch
Pin No.
13
14
15
16
17
18
19
20
21
22
23
24
Pin Name
MUTE
LOUT
OUTS2
OUTS1
OUTR2
OUTR1
OUTF2
OUTF1
VCC
SCL
SDA
GND
Description
External compulsory mute terminal
Output terminal for Level meter
Subwoofer output terminal of 2ch
Subwoofer output terminal of 1ch
Rear output terminal of 2ch
Rear output terminal of 1ch
Front output terminal of 2ch
Front output terminal of 1ch
Power supply terminal
I
2
C Communication clock terminal
I
2
C Communication data terminal
GND terminal
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© 2015 ROHM Co., Ltd. All rights reserved.
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2/31
TSZ02201-0C2C0E100490-1-2
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BD37524FS
Block Diagram
24
23
22
21
VCC
20
19
18
17
16
15
14
13
GND
I
2
C BUS LOGIC
■Fader
Fader
Gain:+15dB to -79dB/1dB step
Gain:+15dB½-79½B/1dB step
★no pop noise
■LPF
fc=55/85/120/160Hz
■Loudness
Loudness
Gain: 20dB to 0dB/1dB step
Gain:20dB½0½B/1½B step
★no pop noise
・½0=250/400/800Hz
・Hicut:1/2/3/4
■3 Band P-EQ (Tone control)
Gain：+20dB½-20dB/1dB step
Gain: +20dB to -20dB/1dB
★no pop noise
・Bass：f0=60/80/100/120Hz
Q=0.5/1.0/1.5/2.0
・Meddle:f0=500/1k/1.5k/2.5kHz
Q=0.75/1/1.25/1.5
・Treble：f0=7.5k/10k/12.5k/15kHz
Q=0.75/1.25
■Volume
Gain: +15dB to -79dB/1dB step
Gain：+15dB½-79dB/1dB step
★no pop noise
■Input Gain
Gain: +20dB to 0dB/1dB step
Gain：+20dB½0dB/1dB step
★no pop noise
Fader★
Fader★
Fader★
Fader★
GND
ISO amp
Input selector (4 single-end and 1 stereo ISO)
GND
ISO amp
250k
7
8
250k
9
250k
10
250k
11
250k
12
250k
Fader★
LPF
★Loudness
★3
Band P-EQ
(Tone control)
★Volume/Mute
Level
meter
★Input
Gain
VCC/2
100k
1
2
3
100k
4
100k
5
100k
6
250k
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© 2015 ROHM Co., Ltd. All rights reserved.
TSZ22111・15・001
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TSZ02201-0C2C0E100490-1-2
16.Dec.2015 Rev.001
BD37524FS
Absolute Maximum Ratings
(Ta=25°C)
Parameter
Power supply Voltage
Input voltage
Power Dissipation
Storage Temperature
Symbol
V
CC
V
IN
Pd
Tstg
3
Rating
10.0
V
CC
+0.3 to GND-0.3
1
(Note 1)
-55 to +150
Unit
V
V
W
°C
(Note 1) When mounted on standard board (70 x 70 x 1.6(mm )), derate by 8mW/°C for Ta above25°C.
Thermal resistance θja = 125(°C/W)
Material : A FR4 grass epoxy board(3% or less of copper foil area)
Caution:
Operating the IC over the absolute maximum ratings may damage the IC. The damage can either be a short circuit between pins or an open circuit
between pins and the internal circuitry. Therefore, it is important to consider circuit protection measures, such as adding a fuse, in case the IC is operated over
the absolute maximum ratings.
Recommended Operating Conditions
Parameter
Power Supply Voltage
Temperature
Symbol
V
CC
Topr
Min
7.0
-40
Typ
－
－
Max
9.5
+85
Unit
V
°C
Electrical Characteristics
(Unless otherwise noted, Ta=25°C, V
CC
=8.5V, f=1kHz, V
IN
=1Vrms, Rg=600Ω, R
L
=10kΩ, A1 input, Input gain 0dB,
Mute OFF, Volume 0dB, Tone control 0dB, Loudness 0dB, LPF OFF, Fader 0dB)
Limit
Parameter
Symbol
Unit
Conditions
Min
Typ
Max
BLOCK
Circuit Current (No Signal)
Voltage Gain
Channel Balance
Total Harmonic Distortion 1
(FRONT,REAR)
Total Harmonic Distortion 2
(SUBWOOFER)
Output Noise Voltage 1
(FRONT,REAR) *
Output Noise Voltage 2
(SUBWOOFER) *
Residual Output Noise Voltage *
I
Q
G
V
CB
THD+N1
THD+N2
V
NO1
V
NO2
V
NOR
－
-1.5
-1.5
－
－
－
－
－
－
－
70
175
2.1
－
38
0
0
0.001
0.002
3.8
4.8
1.8
48
+1.5
+1.5
0.05
0.05
15
15
10
mA
dB
dB
％
％
μVrms
μVrms
μVrms
No signal
G
V
=20log(V
OUT
/V
IN
)
CB = G
V1
-G
V2
V
OUT
=1Vrms
BW=400Hz-30KHz
V
OUT
=1Vrms
BW=400Hz-30KHz
Rg = 0Ω
BW = IHF-A
Rg = 0Ω
BW = IHF-A
Fader = -∞dB
Rg = 0Ω
BW = IHF-A
Rg = 0Ω
CTC=20log(V
OUT
/V
IN
)
BW = IHF-A
f=1KHz
V
RR
=100mVrms
RR=20log(V
CC
IN/V
OUT
)
GENERAL
Crosstalk Between Channels *
CTC
-100
-90
dB
Ripple Rejection
Input Impedance(A, B)
RR
R
IN_S
R
IN_D
V
IM
CTS
-70
100
250
2.3
-100
-40
130
325
－
-90
dB
kΩ
kΩ
Vrms
dB
INPUT SELECTOR
Input Impedance (C,D,E)
Maximum Input Voltage
Crosstalk Between Selectors *
Common Mode Rejection Ratio *
CMRR
50
65
－
dB
INPUT GAIN
Minimum Input Gain
G
IN_MIN
-2
0
+2
dB
Maximum Input Gain
Gain Set Error
G
IN_MAX
G
IN_ERR
18
-2
20
0
22
+2
dB
dB
V
IM
at THD+N(V
OUT
)=1％
BW=400Hz-30KHz
Rg = 0Ω
CTS=20log(V
OUT
/V
IN
)
BW = IHF-A
CP1 and CN input
CP2 and CN input
CMRR=20log(V
IN
/V
OUT
)
BW = IHF-A
Input gain 0dB
V
IN
=100mVrms
G
IN
=20log(V
OUT
/V
IN
)
Input gain 20dB
V
IN
=100mVrms
G
IN
=20log(V
OUT
/V
IN
)
GAIN=+20dB to +1dB
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© 2015 ROHM Co., Ltd. All rights reserved.
TSZ22111・15・001
4/31
TSZ02201-0C2C0E100490-1-2
16.Dec.2015 Rev.001
BD37524FS
Electrical Characteristics - continued
BLOCK
Limit
Parameter
Symbol
Min
－
Typ
Max
Unit
Conditions
Mute ON
G
MUTE
=20log(V
OUT
/V
IN
)
BW = IHF-A
Volume = 15dB
V
IN
=100mVrms
G
V
=20log(V
OUT
/V
IN
)
Volume = -∞dB
G
V
=20log(V
OUT
/V
IN
)
BW = IHF-A
GAIN & ATT=+15dB to -15dB
ATT=-16dB to -47dB
ATT=-48dB to -79dB
Gain=+20dB f=100Hz
V
IN
=100mVrms
G
B
=20log (V
OUT
/V
IN
)
Gain=-20dB f=100Hz
V
IN
=2Vrms
G
B
=20log (V
OUT
/V
IN
)
Gain=+20dB to -20dB f=100Hz
gain=+20dB f=1KHz
V
IN
=100mVrms
G
M
=20log (V
OUT
/V
IN
)
Gain=-20dB f=1KHz
V
IN
=2Vrms
G
M
=20log (V
OUT
/V
IN
)
Gain=+20dB to -20dB f=1KHz
Gain=+20dB f=10kHz
V
IN
=100mVrms
G
T
=20log (V
OUT
/V
IN
)
Gain=-20dB f=10kHz
V
IN
=2Vrms
G
T
=20log (V
OUT
/V
IN
)
Gain=+20dB to -20dB f=10kHz
Fader=15dB
V
IN
=100mVrms
G
F
=20log(V
OUT
/V
IN
)
Fader = -∞dB
G
F
=20log(V
OUT
/V
IN
)
BW = IHF-A
Gain=+15dB to +1dB
ATT=-1dB to -15dB
ATT=-16dB to -47dB
ATT=-48dB to -79dB
V
IN
=100mVrms
THD+N=1%
BW=400Hz-30KHz
Gain 20dB
V
IN
=100mVrms
G
L
=20log(V
OUT
/V
IN
)
GAIN=+20dB to +1dB
MUTE
Mute Attenuation *
G
MUTE
-105
-85
dB
Maximum Gain
G
V_MAX
G
V_MIN
G
V_ERR1
G
V_ERR2
G
V_ERR3
G
B_BST
13
－
-2
-3
-4
18
15
-100
0
0
0
20
17
-85
+2
+3
+4
22
dB
dB
dB
dB
dB
dB
VOLUME
BASS
Maximum Attenuation *
Attenuation Set Error 1
Attenuation Set Error 2
Attenuation Set Error 3
Maximum Boost Gain
Maximum Cut Gain
Gain Set Error
Maximum Boost Gain
G
B_CUT
G
B_ERR
G
M_BST
-22
-2
18
-20
0
20
-18
+2
22
dB
dB
dB
MIDDLE
Maximum Cut Gain
Gain Set Error
Maximum Boost Gain
G
M_CUT
G
M_ERR
G
T_BST
-22
-2
18
-20
0
20
-18
+2
22
dB
dB
dB
TREBLE
Maximum Cut Gain
Gain Set Error
Maximum Boost Gain
G
T_CUT
G
T_ERR
G
F_BST
-22
-2
13
-20
0
15
-18
+2
17
dB
dB
dB
FADER / SUBWOOFER
Maximum Attenuation＊
Gain Set Error
Attenuation Set Error 1
Attenuation Set Error 2
Attenuation Set Error 3
Output Impedance
Maximum Output Voltage
G
F_MIN
G
F
_
ERR
G
F_ERR1
G
F_ERR2
G
F_ERR3
R
OUT
V
OM
G
L_MAX
－
-2
-2
-3
-4
－
2
17
-100
0
0
0
0
－
2.2
20
-90
+2
+2
+3
+4
50
－
23
dB
dB
dB
dB
dB
Ω
Vrms
dB
LOUDNESS
Maximum Gain
Gain Set Error
Maximum Output Voltage
Output Offset Voltage
G
L_ERR
V
L_MAX
V
L_OFF
-2
2.8
－
0
3.1
0
+2
3.5
100
dB
V
mV
VP-9690A(Average value detection, effective value display) filter by Matsushita Communication is used for * measurement.
Phase between input / output is same.
www.rohm.com
© 2015 ROHM Co., Ltd. All rights reserved.
TSZ22111・15・001
Level
meter
5/31
TSZ02201-0C2C0E100490-1-2
16.Dec.2015 Rev.001
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