ROHM BD37541FS Technical data

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Structure

: Silicon Monolithic Integrated Circuit

Product: Sound Processor for car audio

Type:

BD37541FS

Package: SSOP-A32

●Feature

1. Reduce switching noise of input gain control, mute, main volume, fader volume, bass, middle, treble, loudness,
by using advanced switch circuit [Possible to control all steps]

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

3. Built-in differential input selector that can make various combination of single-ended / differential input.

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

5. Decrease the number of external components by built-in 3-band equalizer fi lter.
And, possible to control Q, Gv, fo of 3-band equalizer by I

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

7. It is equipped with output terminals of Subwoofer. Moreover, the stereo signal of the front and rear also can be
output by the I

2

C BUS control.

8. Built-in mixing input.

9. 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.

10. Package is SSOP-A32. Putting input-terminals together and output-terminals together can make PCB layout
easier and can makes area of PCB smaller.

11. It is possible to control by 3.3V / 5V for I

●Absolute Maximum Ratings (Ta=25℃)

Parameter Symbol Limits Unit

Power supply Voltage VCC 10.0 V

Input voltage VIN VCC+0.3～GND-0.3 V

Power Dissipation Pd 950 ※1mW

Storage Temperature T astg -55～+150 ℃

※1 At T a＝25°C or higher, this value is decreaced to 8.5mW/°C

When Rohm standard board is mounted.

Rohm standard board:

Size：70×70×1.6(mm3)

material：FR4 glass-epoxy substrate (copper foil area: not more than 3%).

●Operating Range

Parameter Symbol Min. Typ. Max. Unit

Power supply Voltage VCC 7.0 － 9.5 V

Temperature Topr -40 － +85 ℃

※Design against radiation-proof isn’t made.

2

C BUS.

2

C BUS control freely.

REV . A

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2

)

X

g(

)

●Function

Function Specifications

Input selector

Input gain

Mute

Volume

Bass
Middle
Treble

Fader

Loudness

Mixing Monaural input

Stereo 3 single-end input and 2differential input possible to switch single-end input
0～20dB (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), Q=0.5, 1, 1.5, 2, fo=60, 80, 100, 120Hz
Possible to use advanced switch at changing gain

-20～+20dB (1dB step), Q=0.75, 1, 1.25, 1.5, fo=500, 1k, 1.5k, 2.5kHz
Possible to use advanced switch at changing gain

-20～+20dB (1dB step), Q=0.75, 1.25, fo=7.5k, 10k, 12.5k, 15kHz
Possible to use advanced switch at changing gain
0dB～-79dB (1dB step), -∞dB
Possible to use “Advanced switch” for prevention of switching noise.
0dB～20dB (1dB step)
Possible to use “Advanced switch” for prevention of switching noise.

●Electrical Characteristic

(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, Fader 0dB, Mixing OFF)

Item Symbol

Current upon no signal
Voltage gain
Channel balance

T otal harmonic distortion 1
(FRONT,REAR)

T otal harmonic distortion
(SUBWOOFER)

Output noise voltage 1
(FRONT,REAR)

Output noise voltage 2
(SUBWOOFER)

Residual output noise voltage

Cross-talk between channels

Ripple rejection

Common mode rejection ratio
(D, E)

Maximum input voltage

Maximum gain

Maximum attenuation

Maximum output voltage

Min. Typ. Max.

IQ
GV -1.5 0 1.5 dB Gv=20log(VOUT/VIN)
CB -1.5 0 1.5 dB CB = GV1-GV2

THD+N1
THD+N2

VNO1 － 3.8 15 μVrms
VNO2 － 4.8 15 μVrms

VNOR

CTC

RR

CMRR 50 65 － dB

VIM 2.0 2.2 － Vrms

GV MAX 13 15 17

GV MIN － -100 -85

VOM 2.0 2.2 － Vrms

－ 38 48

－ 0.001 0.05 ％
－ 0.002 0.05 ％

－ 1.8 10

－

－

Limit

-100 -90 dB

-70 -40 dB

Unit Condition

mA No signal

μVrms

dB

dB

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=100Hz
VRR=100mVrms
RR=20log(VOUT/VCCIN

XP1 and XN input
XP2 and XN input
CMRR=20log(VIN/VOUT)
BW = IHF-A,[※
VIM at THD+N(VOUT)=1%
BW=400-30kHz

Volume = 15dB
VIN=100mVrms
Gv=20lo
Volume=-∞dB

Gf=20log(VOUT/VIN)
BW=IHF-A

THD+N=1%
BW=400-30kHz

・・・D,E]

VOUT/VIN

REV . A