ROHM BD37513FS Technical data

Sound Processor Series for Car Audio

Sound Processors with Built-in
2-band Equalizer

BD37513FS,BD37514FS,BD37515FS

●Description
BD37513FS, BD37514FS, BD37515FS are sound pr ocessors built-in 2-band equalizer for car audio. The functions are
stereo 4ch input selector, input-gain control, main volume, loudness, 5ch fader volume (About BD37513FS, 4ch fader
volume are available). Moreover, “Advanced switch circuit”, that is ROHM original technology, can reduce various
switching noise (ex. No-signal, low frequency likes 20Hz & large signal inputs). “Advanced switch” makes control of
microcomputer easier, and can construct high quality car audio system.

●Features

1) Reduce switching noise of input gain control, mute, main volume, fader volume, bass, treble, loudness by using

advanced switch circuit [Possible to control all steps]

2) Built-in 1 differential input selector and 3 single-ended input selectors

3) Built-in ground isolation amplifier inputs, ideal for external stereo input.

4) Built-in input gain controller reduces switching noise for volume of a portable audio input.

5) Decrease the number of external components by built-in 2-band equalizer filter, LPF(BD37515FS) for subwoofer,

loudness filter. And, possible to control Q(BD37514FS, BD37515FS), Gv, fo(BD37514FS, BD37515FS) of 2-band
equalizer, fc of LPF(BD37515FS) for subwoofer and Gv of loudness by I

6) It is possible for the bass, treble to the gain adjustment quantity of ±20dB and 1 dB step gain adjustment.

7) It is equipped with output terminals of Subwoofer(BD37514FS, BD37515FS).

8) Bi-CMOS process is suitable for the design of low current and low energy. And it provides more quality for small

scale regulator and heat in a set.

9) Package is SSOP-A20. Putting input-terminals together and output-terminals together can make PCB layout

easier and can makes area of PCB smaller.

10) It is possible to control by 3.3V / 5V for I

●Applications
It is the optimal for the car audio. Besides, it is possible to use for the audio equipment of mini Compo, micro Compo, TV
etc with all kinds.

2

C BUS.

2

C BUS control

No.10085EAT02

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© 2010 ROHM Co., Ltd. All rights reserved.

2010.03 - Rev.A

BD37513FS,BD37514FS,BD37515FS

●Line up matrix

Function BD37513FS BD37514FS BD37515FS Specifications

Input selector ○ ○ ○

Input gain ○ ○ ○

Mute ○ ○ ○

Volume ○ ○ ○

Bass

Treble ○ ○ ○

Fader

Loudness ○ ○ ○

LPF

●Absolute maximum ratings (Ta=25℃)

○ ○ ○

○ ○ ○

× × ○

Technical Note

・Stereo 3 input
・Differential 1 input
・+20～0dB（1dB step）
・ Possible to use “Advanced switch” for prevention of

switching noise.

・ Possible to use “Advanced switch” for prevention of

switching noise.

・+15dB～-79dB（1dB step）, -∞dB
・ Possible to use “Advanced switch” for prevention of

switching noise.

・ +20～-20dB（1dB step）
・Possible to use “Advanced switch” at changing gain
・Q=0.5, 1, 1.5, 2(BD37513FS:1)
・fo=60, 80, 100, 120Hz(BD37513FS：100Hz)
・ +20～-20dB（1dB step）
・Possible to use “Advanced switch” at changing gain
・Q=0.75, 1.25(BD37513FS：1.25)
・fo=7.5k, 10k, 12.5k, 15kHz(BD37513FS：10kHz)
・+15dB～-79dB(1dB step), -∞dB

(BD37513FS,BD37514FS : 0dB～-79dB, -∞dB)

・ Possible to use “Advanced switch” for prevention of

switching noise.

・20dB～0dB(1dB step)
・fo=800Hz
・ Possible to use “Advanced switch” for prevention of

switching noise.

・fc=55/85/120/160Hz, pass
・Phase shift (0°/180°)

Item Symbol Rating Unit

Power supply Voltage VCC 10.0 V

Input voltage Vin VCC+0.3～GND-0.3 V

Power Dissipation Pd 940 ※1 mW

Storage Temperature Tastg

※This value decreases 7.5mW/℃ for Ta=25℃ or more.
ROHM standard board shall be mounted.
Thermal resistance θja = 133(℃/W)
ROHM Standard board

Size：70×70×1.6(㎣)
Material：A FR4 grass epoxy board(3% or less of copper foil area)

●Operating conditions

Item Symbol MIN TYP MAX Unit

Power supply Voltage VCC 7.0 ― 9.5 V

Temperature Topr -40 ― +85 V

-55～+150 ℃

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© 2010 ROHM Co., Ltd. All rights reserved.

2010.03 - Rev.A

BD37513FS,BD37514FS,BD37515FS

Technical Note

●Electrical characteristics

(Unless specified particularly, Ta=25℃, VCC=8.5V, f=1kHz, Vin=1Vrms, Rg=600Ω, RL=10kΩ, A input, Input gain 0dB,
Mute off, Volume 0dB, Tone control 0dB, Loudness 0dB, LPF OFF(BD37515FS), Fader 0dB)

Limit

Unit Condition

BLOCK

Item Symbol

Min. Typ. Max.
Current upon no signal IQ － 38 48 mA No signal
Voltage gain GV -1.5 0 +1.5 dB Gv=20log(VOUT/VIN)

Channel balance -1.5 0 +1.5 dB CB = GV1-GV2
Total harmonic distortion 1

(FRONT,REAR)

THD+N1

－

0.001 0.05

％

T otalharmonicdistortion2
(SUBWOOFER)

THD+N2

－ 0.002 0.05 ％
(BD37514FS, BD37515FS)
Output noise voltage 1
(FRONT,REAR)＊

Output noise voltage 2

GENERAL

(SUBWOOFER)＊

－ 3.8 15 μVrms

V

NO1

－ 4.8 15 μVrms

V

NO2

(BD37514FS, BD37515FS)
Residual output noise voltage＊ V

－ 1.8 10 μVrms

NOR

Cross-talk between channels＊ CTC － -100 -90 dB

Ripple rejection RR － -70 -40 dB
Input impedance(A,B) R

Input impedance (C,D) R

70 100 130 kΩ

IN_S

175 250 325 kΩ

IN_D

Maximum input voltage VIM 2.1 2.3 － Vrms

Cross-talk between selectors＊ CTS － -100 -90 dB

INPUT SELECTOR

Common mode rejection ratio＊ CMRR 50 － dB

Minimum input gain G

Maximum input gain G

IN MIN

IN MAX

-2 0 +2 dB

+18 +20 +22 dB

INPUT GAIN

Gain set error G

Mute attenuation＊ G

MUTE

Maximum gain G

Maximum attenuation＊ G

IN ERR

MUTE

V MAX

V MIN

-2 0 +2 dB GAIN=+20～+1dB

－ -105 -85 dB

+13 +15 +17 dB

－ -100 -85 dB

VOLUME

Attenuation set error 1 G
Attenuation set error 2 G
Attenuation set error 3 G

V ERR1
V ERR2
V ERR3

-2 0 +2 dB

-3 0 +3 dB ATT=-16dB～-47dB

-4 0 +4 dB ATT=-48dB～-79dB

VOUT=1Vrms
BW=400-30KHz

VOUT=1Vrms
BW=400-30KHz

Rg = 0Ω
BW = IHF-A

Rg = 0Ω
BW = IHF-A

Fader = -∞dB
Rg = 0Ω
BW = IHF-A
Rg = 0Ω
CTC=20log(VOUT/VIN)
BW = IHF-A
f=1kHz
VRR=100mVrms
RR=20log(VCC IN/VOUT)

VIM at THD+N(VOUT)=1％
BW=400-30KHz
Rg = 0Ω
CTS=20log(VOUT/VIN)
BW = IHF-A

DP1 and DN input
DP2 and DN input
CMRR=20log(VIN/VOUT)
BW = IHF-A
Input gain 0dB

VIN=100mVrms
Gin=20log(VOUT/VIN)
Input gain 20dB
VIN=100mVrms
Gin=20log(VOUT/VIN)

Mute ON
Gmute=20log(VOUT/VIN)
BW = IHF-A

Volume = 15dB
VIN=100mVrms
Gv=20log(VOUT/VIN)
Volume = -∞dB
Gv=20log(VOUT/VIN)
BW = IHF-A

GAIN & ATT=+15dB～-15dB

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© 2010 ROHM Co., Ltd. All rights reserved.

2010.03 - Rev.A

BD37513FS,BD37514FS,BD37515FS

BLOCK

Maximum boost gain

BASS

Maximum cut gain

Gain set error
Maximum boost gain

Maximum cut gain

TREBLE

Gain set error
Maximum boost gain

(BD37515FS)

Maximum attenuation* G

Gain set error (BD37515FS)
Attenuation set error 1
Attenuation set error 2

FADER / SUBWOOFER

Attenuation set error 3
Output impedance

Maximum output voltage

Maximum gain

LOUDNESS

Gain set error

VP-9690A(Average value detection, effective value display) filter by Matsushita Communication is used for ＊ measurement.

Phase between input / output is same.

Item Symbol

G

B BST

G

B CUT

G

B ERR

G

T BST

G

T CUT

G

T ERR

G

F BST

F MIN

G

F ERR

G

F ERR1

G

F ERR2

G

F ERR3

R

OUT

V

OM

G

L MAX

G

L ERR

Min. Typ. Max.

+18 +20 +22 dB

-22 -20 -18 dB

+18 +20 +22 dB

-23 -20 -17 dB

-2 0 +2 dB Gain=+20～-20dB f=10kHz

+13 +15 +17 dB

-2 0 +2 dB Gain=+1～+15dB

- － 50 Ω VIN=100mVrms

2 2.2

+17 +20 +23 dB

-2 0 +2 dB GAIN=+20～+1dB

Limit

Unit Condition

-2 0 +2 dB Gain=+20～-20dB f=100Hz

－

-100 -90 dB

-2 0 +2 dB ATT=0～-15dB

-3 0 +3 dB

-4 0 +4 dB ATT=-48～-79dB

－

Vrms

Technical Note

Gain=+20dB f=100Hz
VIN=100mVrms
GB=20log (VOUT/VIN)
Gain=-20dB f=100Hz
VIN=2Vrms
GB=20log (VOUT/VIN)

Gain=+20dB f=10kHz
VIN=100mVrms
GT=20log (VOUT/VIN)
Gain=-20dB f=10kHz
VIN=2Vrms
G

=20log (VOUT/VIN)

T

Fader=15dB
V

=100mVrms

IN

G

=20log(VOUT/VIN)

F

Fader = -∞dB
G

=20log(VOUT/VIN)

F

BW = IHF-A

ATT=-16～-47dB

THD+N=1％
BW=400-30KHz
Gain 20dB
VIN=100mVrms
G

=20log(VOUT/VIN)

L

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2010.03 - Rev.A

BD37513FS,BD37514FS,BD37515FS

%

u

dB

● Electrical characteristic curves (Reference data)

Technical Note

50

40

30

Iq[mA]

20

10

0

0246810

VCC[V]

Fig.1 Iq vs Vcc

25
20
15
10

5

Gain[dB]

0

-5

-1 0

-1 5

-2 0

-2 5
10 100 1k 10k 100k

BASS GAIN : -20～+20dB
/1dB step
fo : 60Hz Q : 0.5

Frequency [Hz]

Fig.4 Bass Gain vs Freq

25

TREBLE GAIN:-20～+20dB

20

/1dB step
fo : 7.5kHz Q : 0.75

15
10

5
0

-5

Gain (dB)

Gain[dB]

-10

-15

-20

-25
10 100 1k 10k 100k

Fig.7 Treble Gain vs Freq

Frequency [Hz]

Frequency (Hz)

10

1

0.1

THD+N (

THD+N[%]

0.01

100Hz

10kHz

1kHz

0.001

0.0 0 1 0.0 1 0.1 1 10

Vout [Vrms]

Fig.2 Thd vs Vo

Vout (V)

10

1

0.1

0.01

0.001

5
4
3

Vo

Vin[Vrms]

2
1

Gain[dB]

0

Gain (

-1

10 100 1k 10k 100k

-2

-3

-4

-5

Fig.3 Gain vs Freq

Gain=0dB

Frequency [Hz]

Frequency (Hz)

25
20
15
10

5

Gain[dB]

0

-5

-1 0

-1 5

-2 0

-2 5
10 100 1k 10k 100k

fo : 60/80/100/120Hz
BASS GAIN : ±20dB
Q : 0.5

Frequency [Hz]

Fig.5 Bass fo vs Freq

25

fo : 7.5k/10k/12.5k/15kHz

20

TREBLE GAIN : ±20dB
Q : 0.75

15
10

5
0

-5

Gain[dB]

-10

-15

-20

-25
10 100 1k 10k 100k

Frequency [Hz]

Fig.8 Treble fo vs Freq

25
20
15
10

5
0

Gain[dB]

-5

-1 0

-1 5

-2 0

-2 5
10 100 1k 10k 100k

Q : 0.5/1/1.5/2
BASS GAIN : ±20dB
fo : 60Hz

Frequency [Hz]

Fig.6 B Bass Q vs Freq

25

Q : 0.75/1.25

20

TREBLE GAIN : ±20dB
fo : 7.5kHz

15
10

5
0

-5

Gain (dB)

Gain[dB]

-10

-15

-20

-25
10 100 1k 10k 100k

Frequency [Hz]

Frequency (Hz)

Fig.9 Treble Q vs Freq

1000

Din-Audio IHF-A

100

10

Output Noise[uVrms]

出力雑音電圧[uVrms]

1

-80 -70 -60 -50 -40 -30 -20 -10 0 10 20

Volume Gain[dB]

Fig.10 Volume Gain vs Noise

1000

DIN-Audio IHF-A

100

10

Output Noise[uVrms]

出力雑音電圧 [uVrms]

1

-20 -15 -10 -5 0 5 10 15 20

Bass Gain [dB]

Fig.11 Bass Gain vs Noise

1000

DIN-Audio IHF-A

100

10

出力雑音電圧 [uVrms]

Output Noise[uVrms]

1

-20 -15 -10 -5 0 5 10 15 20
Treble Gain [dB]

Fig.12 Treble Gain vs Noise

Fig.5～6 : Bass fo/Q are changeable in only BD37514FS and BD37515FS.fo/Q=100Hz/1.0 and unchangeabl e in BD37513FS.
Fig.8～9 : Treble fo/Q are changeable in only BD37514FS and BD37515FS.fo/Q=10kHz/1.25 and unchangeable in BD37513FS.

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© 2010 ROHM Co., Ltd. All rights reserved.

2010.03 - Rev.A

BD37513FS,BD37514FS,BD37515FS

B

Fr
eq
ue

0

nc

y

-1 0

-2 0

-3 0

-4 0

Gain (d

Gain[dB]

-5 0

-6 0

-7 0
10 100 1k 10k 100k

Frequency (Hz)

Fig.13 CMRR vs Freq

[Hz]

Vo [Vrms]

Gain[dB]

Fig.16 Advanced Switch 2

2.5

2.0

1.5

1.0

最大出力[Vrms]

0.5

0.0
100 1000 10000 100000

Rload [ohm]

出力負荷[ohm]

Fig.14 Rload vs Vo

Technical Note

Fig.15 Advanced Switch 1

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© 2010 ROHM Co., Ltd. All rights reserved.

2010.03 - Rev.A

BD37513FS,BD37514FS,BD37515FS

●Block diagram and pin configuration

20 19 18 17 16 15 14 13 12 11

GND

I2C BUS LOGIC

■Fader
Gain:0dB～-79ｄB/1dB step

★no pop noise

■Loudness
20dB～0ｄB/1ｄB step

★no pop noise

・ｆ0=800
・Hicut1/2/3/4

■2 Band EQ (Tone control)
Gain：+20dB～-20dB/1dB

★no pop noise

・Bass：f0=100Hz,

Q=1.0

・Treble：f0=10kHz

Q=1.25

■Volume
Gain:+15dB～-79dB/1dB step

★no pop noise

■Input Gain
Gain:+20dB～0dB/1dB step

★no pop noise

Input selector (3 single-end and 1 stereo ISO)

VCC/2

100k

100k 100k 100k 250k 250k 250k

1 2 3 4 5 6 7 8 9 10

Descriptions of terminal

Terminal

No.

Terminal

Name

Description

1 FIL VCC/2 terminal 11 MUTE External compulsory mute terminal
2 A1 A input terminal of 1ch 12 TEST1 Test Pin
3 A2 A input terminal of 2ch 13 OUTR2 Rear output terminal of 2ch
4 B1 B input terminal of 1ch 14 OUTR1 Rear output terminal of 1ch
5 B2 B input terminal of 2ch 15 OUTF2 Front output terminal of 2ch
6 C1 C input terminal of 1ch 16 OUTF1 Front output terminal of 1ch
7 C2 C input terminal of 2ch 17 VCC Power supply terminal
8 DP1 D positive input terminal of 1ch 18 SCL I2C Communication clock terminal
9 DN D negative input terminal 19 SDA I2C Communication data terminal

10 DP2 D positive input terminal of 2ch 20 GND GND terminal

VCC

Fader★

Fader★

★Loudness

★2 Band EQ

(Tone control)

★Volume/Mute

★Input Gain

Fig.17 BD37513FS

Terminal

No.

Fader★

Fader★

GND

ISO amp

Terminal

Name

GND

ISO amp

250k

Technical Note

250k

Description

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© 2010 ROHM Co., Ltd. All rights reserved.

2010.03 - Rev.A

BD37513FS,BD37514FS,BD37515FS

20 19 18 17 16 15 14 13 12 11

GND

I2C BUS LOGIC

■Fader
Gain:0dB～-79ｄB/1dB step

★no pop noise

■Loudness
20dB～0ｄB/1ｄB step

★no pop noise

・ｆ0=800
・Hicut1/2/3/4

■2 Band P-EQ (Tone control)
Gain：+20dB～-20dB/1dB

★no pop noise

・Bass：f0=60/80/100/120Hz,

Q=0.5/1.0/1.5/2.0

・Treble：f0=7.5k/10k/12.5k/15kHz

Q=0.75/1.25

■Volume
Gain:+15dB～-79dB/1dB step

★no pop noise

■Input Gain
Gain:+20dB～0dB/1dB step

★no pop noise

Input selector (3 single-end and 1 stereo ISO)

VCC/2

1 2 3 4 5 6 7 8 9 10

100k

100k 100k 100k 250k 250k

Descriptions of terminal

Terminal

No.

Terminal

Name

Description

1 FIL VCC/2 terminal 11 MUTE External compulsory mute terminal
2 A1 A input terminal of 1ch 12 OUTS Subwoofer output terminal
3 A2 A input terminal of 2ch 13 OUTR2 Rear output terminal of 2ch
4 B1 B input terminal of 1ch 14 OUTR1 Rear output terminal of 1ch
5 B2 B input terminal of 2ch 15 OUTF2 Front output terminal of 2ch
6 C1 C input terminal of 1ch 16 OUTF1 Front output terminal of 1ch
7 C2 C input terminal of 2ch 17 VCC Power supply terminal
8 DP1 D positive input terminal of 1ch 18 SCL I2C Communication clock terminal
9 DN D negative input terminal 19 SDA I2C Communication data terminal

10 DP2 D positive input terminal of 2ch 20 GND GND terminal

VCC

Fader★

Fader★

★Loudness

★2 Band P-EQ

(Tone control)

★Volume/Mute

★Input Gain

Fig.18 BD37514FS

Terminal

No.

Fader★

Fader★

GND

ISO amp

250k

Terminal

Name

Fader★

ISO amp

250k

Technical Note

GND

250k

Description

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© 2010 ROHM Co., Ltd. All rights reserved.

2010.03 - Rev.A

BD37513FS,BD37514FS,BD37515FS

20 19 18 17 16 15 14 13 12 11

GND

I2C BUS LOGIC

■Fader
Gain:+15dB～-79ｄB/1dB step

★no pop noise

■LPF
fc=55/85/120/160Hz

■Loudness
20dB～0ｄB/1ｄB step

★no pop noise

・ｆ0=800
・Hicut1/2/3/4

■2 Band P-EQ (Tone control)
Gain：+20dB～-20dB/1dB

★no pop noise

・Bass：f0=60/80/100/120Hz,

Q=0.5/1.0/1.5/2.0

・Treble：f0=7.5k/10k/12.5k/15kHz

Q=0.75/1.25

■Volume
Gain:+15dB～-79dB/1dB step

★no pop noise

■Input Gain
Gain:+20dB～0dB/1dB step

★no pop noise

Input selector (3 single-end and 1 stereo ISO)

VCC/2

1 2 3 4 5 6 7 8 9 10

100k

100k 100k 100k 250k 250k 250k

Descriptions of terminal

Terminal

No.

Terminal

Name

Description

1 FIL VCC/2 terminal 11 MUTE External compulsory mute terminal
2 A1 A input terminal of 1ch 12 OUTS Subwoofer output terminal
3 A2 A input terminal of 2ch 13 OUTR2 Rear output terminal of 2ch
4 B1 B input terminal of 1ch 14 OUTR1 Rear output terminal of 1ch
5 B2 B input terminal of 2ch 15 OUTF2 Front output terminal of 2ch
6 C1 C input terminal of 1ch 16 OUTF1 Front output terminal of 1ch
7 C2 C input terminal of 2ch 17 VCC Power supply terminal
8 DP1 D positive input terminal of 1ch 18 SCL I2C Communication clock terminal
9 DN D negative input terminal 19 SDA I2C Communication data terminal

10 DP2 D positive input terminal of 2ch 20 GND GND terminal

VCC

Fader★

★Loudness

★2 Band P-EQ

(Tone control)

★Volume/Mute

★Input Gain

Fig.19 BD37515FS

Fader★

Terminal

No.

Fader★

Fader★

LPF

GND

ISO amp

Terminal

Name

Fader★

ISO amp

250k

Technical Note

GND

250k

Description

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© 2010 ROHM Co., Ltd. All rights reserved.

2010.03 - Rev.A