Datasheet
Sound Processor
with Built-in 3-band Equalizer
BD37531FV
General Description
BD37531FV is a sound processor with built-in 3-band
equalizer for car audio. A stereo input selector is
available that functions to switch single end input and
ground isolation input, input-gain control, main volume,
loudness and 5ch fader volume. Moreover, “Advanced
switch circuit”, which is an original ROHM technology,
can reduce various switching noise (ex. No-signal, low
frequency like 20Hz & large signal inputs). Also,
“Advanced switch” makes microcomputer control
easier and constructs a high quality car audio system.
Key Specifications
Power Supply Voltage Range:
Circuit Current (No signal) :
Total Harmonic Distortion 1:
(FRONT,REAR)
Total Harmonic Distortion 2:
(SUBWOOFER)
Maximum Input voltage:
Cross-talk Between Selectors:
Volume Control Range:
Output Noise Voltage 1:
(FRONT,REAR)
Output Noise Voltage 2:
(SUBWOOFER)
Residual Output Noise Voltage:
Operating Temperature Range:
7.0V to 9.5V
38mA(Typ)
0.001%(Typ)
0.002%(Typ)
2.3Vrms (Typ)
-100dB (Typ)
+15dB to -79dB
3.8µVrms(Typ)
4.8µVrms(Typ)
1.8µVrms(Typ)
-40°C to +85°C
Features
Reduced switching noise of input gain control,
mute, main volume, fader volume, bass, middle,
treble, loudness by using advanced switch circuit
Built-in differential input selector that can make
various combination of single-ended / differential
input.
Built-in ground isolation amplifier inputs, which is
ideal for external stereo input.
Built-in input gain controller reduces volume
switching noise of a portable audio input.
Decreased number of external components due to
built-in 3-band equalizer filter and loudness filter. It
is possible to freely control the Q, Gv, fo of the
3-band equalizer,
and Gv of the loudness
2
C BUS control
through the I
A gain adjustment quantity of ±20dB with a 1 dB
step gain adjustment is possible for the bass,
middle and treble.
Equipped with terminals for the subwoofer outputs.
Also, the audio signal outputs of the front, rear and
subwoofer can be chosen using the I
2
C BUS
control.
Energy-saving design resulting in low current
consumption is achieved utilizing the BiCMOS
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 control I
2
C BUS with 3.3V / 5V.
Package
W(Typ) x D(Typ) x H(Max)
SSOP-B28
10.0mm x 7.60mm x 1.35mm
Applications
It is optimal for car audio systems. It can also be used
for audio equipment of mini Compo, micro Compo, TV,
etc.
○Product
structure：Silicon monolithic integrated circuit
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© 2015 ROHM Co., Ltd. All rights reserved.
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○This
product has no designed protection against radioactive rays
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BD37531FV
Typical Application Circuit
BD37531FV
Pin Configuration
A1
A2
B1
B2
C1
C2
DP1
DN
DP2
1
2
3
4
5
6
7
8
9
TOP VIEW
28
27
26
25
24
23
22
21
20
19
18
17
16
15
FIL
GND
SDA
SCL
VCC
OUTF1
OUTF2
OUTR1
OUTR2
OUTS1
OUTS2
TEST3
TEST2
MUTE
EP1 10
EN1
EN2
EP2
11
12
13
TEST1 14
Pin Descriptions
Pin No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Pin Name
A1
A2
B1
B2
C1
C2
DP1
DN
DP2
EP1
EN1
EN2
EP2
TEST1
Description
A input terminal of 1ch
A input terminal of 2ch
B input terminal of 1ch
B input terminal of 2ch
C input terminal of 1ch
C input terminal of 2ch
D positive input terminal of 1ch
D negative input terminal
D positive input terminal of 2ch
E positive input terminal of 1ch
E negative input terminal of 1ch
E negative input terminal of 2ch
E positive input terminal of 2ch
Test Pin
Pin No.
15
16
17
18
19
20
21
22
23
24
25
26
27
28
Pin
Name
MUTE
TEST2
TEST3
OUTS2
OUTS1
OUTR2
OUTR1
OUTF2
OUTF1
VCC
SCL
SDA
GND
FIL
Description
External compulsory mute terminal
Test Pin
Test Pin
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
VCC/2 terminal
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© 2015 ROHM Co., Ltd. All rights reserved.
TSZ22111・15・001
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TSZ02201-0C2C0E100520-1-2
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BD37531FV
Block Diagram
28
27
26
25
24
VCC
23
22
21
20
19
18
17
16
15
VCC/2
GND
I
2
C BUS LOGIC
Fader
■Fader
Gain:0dB to -79dB/1dB step
Gain:0dB½-79½B/1dB step
★no pop noise
Loudness
■Loudness
Gain:+20dB to 0dB/1dB step
Gain:20dB½0½B/1½B step
★no pop noise
・½0=250/400/800Hz
・Hicut1/2/3/4
■3 Band P-EQ (Tone control)
Gain: +20dB to -20dB/1dB Step
Gain：+20dB½-20dB/1dB step
★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
Input selector (3 single-end and 2 stereo ISO)
GND
ISO amp
100k
1
2
100k
3
100k
4
100k
5
100k
6
100k
7
250k
8
Fader★
★Loudness
★3
Band P-EQ
(Tone control)
★Volume/Mute
★Input
Gain
Fader★
Fader★
250k
GND
ISO amp
250k
9
Fader★
10
GND
ISO amp
250k
11
250k
Fader★
GND
ISO amp
250k
12
13
250k
14
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© 2015 ROHM Co., Ltd. All rights reserved.
TSZ22111・15・001
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BD37531FV
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
1.06
(Note 1)
-55 to +150
Unit
V
V
W
°C
(Note 1) When mounted on ROHM standard board (70 x 70 x 1.6(mm ), derate by 8.5mW/°C for Ta above 25°C.
Thermal resistance θja = 117.6(°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
Limit
7.0 to 9.5
-40 to +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, Fader 0dB)
Limit
BLOCK
Parameter
Circuit Current
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 *
Symbol
I
Q
G
V
CB
THD+N1
THD+N2
V
NO1
V
NO2
V
NOR
Min
－
-1.5
-1.5
－
－
－
－
－
－
－
70
175
2.1
－
Typ
38
0
0
0.001
0.002
3.8
4.8
1.8
Max
48
+1.5
+1.5
0.05
0.05
15
15
10
Unit
mA
dB
dB
％
％
μVrms
μVrms
μVrms
Conditions
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, C)
Input Impedance (D, E)
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
Maximum Input Voltage
Crosstalk Between Selectors *
Common Mode Rejection Ratio *
(D, E)
CMRR
50
65
－
dB
V
IM
at THD+N(V
OUT
)=1％
BW=400Hz-30KHz
Rg = 0Ω
CTS=20log(V
OUT
/V
IN
)
BW = IHF-A
XP1 and XN input
XP2 and XN input
CMRR=20log(V
IN
/V
OUT
)
BW = IHF-A,[*X・・・D,E]
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© 2015 ROHM Co., Ltd. All rights reserved.
TSZ22111・15・001
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TSZ02201-0C2C0E100520-1-2
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BD37531FV
Electrical Characteristics – continued
BLOCK
Limit
Parameter
Symbol
Min
Typ
Max
Unit
Conditions
INPUT GAIN
Minimum Input Gain
G
IN_MIN
-2
0
+2
dB
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
Mute ON
G
MUTE
=20log(V
OUT
/V
IN
)
BW = IHF-A
Volume = 15dB
V
IN
=100mVrms
Gv=20log(V
OUT
/V
IN
)
Volume = -∞dB
Gv=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
GB=20log (V
OUT
/V
IN
)
Gain=-20dB f=100Hz
V
IN
=2Vrms
GB=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
GT=20log (V
OUT
/V
IN
)
Gain=-20dB f=10kHz
V
IN
=2Vrms
GT=20log (V
OUT
/V
IN
)
Gain=+20dB to -20dB
f=10kHz
Fader = -∞dB
GF=20log(V
OUT
/V
IN
)
BW = IHF-A
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
GL=20log(V
OUT
/V
IN
)
GAIN=+20dB to +1dB
Maximum Input Gain
Gain Set Error
G
IN_MAX
G
IN_ERR
G
MUTE
G
V_MAX
G
V_MIN
G
V_ERR1
G
V_ERR2
G
V_ERR3
G
B_BST
G
B_CUT
G
B_ERR
G
M_BST
G
M_CUT
G
M_ERR
G
T_BST
G
T_CUT
G
T_ERR
G
F_MIN
G
F_ERR1
G
F_ERR2
G
F_ERR3
R
OUT
V
OM
G
L_MAX
+18
-2
－
13
－
-2
-3
-4
18
-22
-2
18
-22
-2
18
-22
-2
－
-2
-3
-4
－
2
17
+20
0
-105
15
-100
0
0
0
20
-20
0
20
-20
0
20
-20
0
-100
0
0
0
－
2.2
20
+22
+2
-85
17
-85
+2
+3
+4
22
-18
+2
22
-18
+2
22
-18
+2
-90
+2
+3
+4
50
－
23
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
Ω
Vrms
dB
MUTE
VOLUME
Mute Attenuation＊
Maximum Gain
Maximum Attenuation *
Attenuation Set Error 1
Attenuation Set Error 2
Attenuation Set Error 3
Maximum Boost Gain
BASS
Maximum Cut Gain
Gain Set Error
Maximum Boost Gain
Maximum Cut Gain
Gain Set Error
Maximum Boost Gain
TREBLE
MIDDLE
Maximum Cut Gain
Gain Set Error
Maximum Attenuation＊
Attenuation Set Error 1
Attenuation Set Error 2
Attenuation Set Error 3
Output Impedance
Maximum Output
Voltage
Maximum Gain
LOUDNESS
FADER /
SUBWOOFER
Gain Set Error
G
L_ERR
-2
0
+2
dB
VP-9690A(Average value detection, effective value display) filter by Matsushita Communication is used for * measurement.
Phase between input / output is same.
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© 2015 ROHM Co., Ltd. All rights reserved.
TSZ22111・15・001
5/30
TSZ02201-0C2C0E100520-1-2
16.Dec.2015 Rev.001
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