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ROHM BD37524FS Data Sheet

Summary

Enhance your car or portable audio system with this advanced sound processor featuring a built-in 3-band equalizer. It provides critical control over volume, equalization (bass, middle, treble), and includes proprietary advanced switching technology to minimize noisy signal interference. Designed for professional use in automotive, mini compo, and TV audio equipment, the manual offers comprehensive technical specifications covering inputs, gain stages, and filter controls, making it an optimal solution for superior sound quality system design.

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Sound Processor Series for Car Audio

Sound Processor with Built-in 3-band Equalizer

No.10085EAT05

BD37524FS

●Description BD37524FS is sound processors built-in 3-band equalizer for car audio. The functions are stereo 5ch input selector, input-gain control, main volume, loudness, 5ch fader volume, LPF for subwoofer, level meter. 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 4 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 3-band equalizer filter, LPF for subwoofer, loudness filter. And, possible to control Q, Gv, fo of 3-band equalizer and fc of LPF, fo, Gv of loudness by I2C BUS control freely 6) It is possible for the bass, middle, and treble to the gain adjustment quantity of ±20d B and 1 d B step gain adjustment. 7) Terminals for the subwoofer outputs are equipped. 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-A24. 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 I2C BUS.

●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.

www.rohm.com 2010.03 - Rev.A 1/25 © 2010 ROHM Co., Ltd. All rights reserved.

Page Summary Contents For ROHM BD37524FS Data Sheet

Page 1 Sound Processor Series for Car Audio Sound Processor with Built-in 3-band Equalizer No.10085EAT05 BD37524FS ●Description BD37524FS is sound processors built-in 3-band equalizer for car audio. The func...
Page 2 BD37524FS Technical Note ●Line up matrix Function Specifications ・Stereo 4 input Input selector ・Differential 1 input ・0~20d B(1d B step) Input gain ・Possible to use “Advanced switch” for prevention o...
Page 3 BD37524FS Technical Note ●Electrical characteristics Minimum input gain GIN MIN -2 0 +2 d B (Unless specified particularly, Ta=25℃, VCC=8.5V, f=1k Hz, Vin=1Vrms, Rg=600Ω, RL=10kΩ, A1 input, Input gain...
Page 4 BD37524FS Technical Note Limit Item Symbol Unit Condition Min. Typ. Max. Gain=+20d B f=100Hz Maximum boost gain GB BST 18 20 22 d B VIN=100m Vrms GB=20log (VOUT/VIN) Gain=-20d B f=100Hz Maximum cut ga...
Page 5 BD37524FS Technical Note in [d in [d in [d ai (d Iq [m ●Electrical characteristic curves (Reference data) 10k Hz 1k Hz Gain=0d B 100Hz Frequency [Hz] VCC[V] Vout [Vrms] in [d Frequency (Hz) Fig.1 Iq v...
Page 6 BD37524FS Technical Note tp is e[ rm rm s] s] tp is e[ [u rm rm s] s] DIN-Audio IHF-A DIN-Audio IHF-A Din-Audio IHF-A Volume Gain[d B] Bass Gain [d B] Middle Gain [d B] Fig.13 Volume Gain vs Noise Fig...
Page 7 BD37524FS Technical Note ●Block diagram and pin configuration GND I2C BUS LOGIC ■Fader Gain:+15d B~-79dB/1d B step ★no pop noise ■LPF fc=55/85/120/160Hz ■Loudness ad r★ Gain:20d B~0dB/1dB step ★no pop...
Page 8 BD37524FS Technical Note ●Timming Chart CONTROL SIGNAL SPECIFICATION (1) Electrical specifications and timing for bus lines and I/O stages t BUF t F t HD;STA t SP t LOW t R t HD;STA t HIGH t HD;DAT t ...
Page 9 BD37524FS Technical Note Table 2 Characteristics of the SDA and SCL I/O stages for I2C-bus devices Fast-mode devices Parameter Symbol Unit Min. Max. 10 LOW level input voltage: VIL -0.3 1 V 11 HIGH le...
Page 10 BD37524FS Technical Note (2)I2C BUS FORMAT MSB LSB MSB LSB MSB LSB S Slave Address A Select Address A Data A P 1bit 8bit 1bit 8bit 1bit 8bit 1bit 1bit S = Start conditions (Recognition of start bit) S...
Page 11 BD37524FS Technical Note (5)Select Address & Data Select MSB Data LSB Items Address (hex) D7 D6 D5 D4 D3 D2 D1 D0 Advanced Advanced switch time Advanced switch time Initial setup 1 01 switch of In...
Page 12 BD37524FS Technical Note Select address 01 (hex) MSB Advanced switch time of Mute LSB Time D7 D6 D5 D4 D3 D2 D1 D0 0.6msec 0 0 Advanced Advanced switch time 1.0msec 0 1 Switch of Input gain/Volume 0 0...
Page 13 BD37524FS Technical Note Select address 05(hex) OUT OUT MSB Input Selector LSB C diff CP1 CP2 0 1 1 0 D D1 D2 1 0 1 0 0 0 0 0 E E1 E2 1 0 1 1 Input SHORT 1 0 0 1 Prohibition Other setting Input SHORT:...
Page 14 BD37524FS Technical Note Select address 20, 28, 29, 2A, 2B, 2C (hex) MSB Vol, Fader Gain / Attenuation LSB Gain & ATT Prohibition Prohibition : : : : : : : : : Initial condition www.rohm.com 2010....
Page 15 BD37524FS Technical Note Select address 41(hex) MSB Bass Q factor LSB Q factor 0 0 Bass fo 0 0 MSB Bass fo LSB fo D7 D6 D5 D4 D3 D2 D1 D0 60Hz 0 0 80Hz 0 1 Bass 100Hz 1 0 Q factor 120Hz 1 1 Select add...
Page 16 BD37524FS Technical Note Select address 51, 54, 57 (hex) MSB Bass/ Middle/ Treble Gain LSB Gain D7 D6 D5 D4 D3 D2 D1 D0 0d B 0 0 0 0 0 1d B 0 0 0 0 1 2d B 0 0 0 1 0 3d B 0 0 0 1 1 4d B 0 0 1 0 0 5d B ...
Page 17 BD37524FS Technical Note Select address 75 (hex) MSB Loudness Hicut LSB Mode D7 D6 D5 D4 D3 D2 D1 D0 Hicut1 0 0 Hicut2 0 1 Loudness Gain Hicut3 1 0 Hicut4 1 1 MSB Loudness Gain LSB Gain D7 D6 D5 D4 D3...
Page 18 BD37524FS Technical Note Volume / Fader volume attenuation of the details :Initial condition www.rohm.com 2010.03 - Rev.A 18/25 © 2010 ROHM Co., Ltd. All rights reserved.
Page 19 BD37524FS Technical Note About Level meter (1) The operation of circuit Level meter is a function which gives DC voltage proportional to the size of signal of sound. It detects the peak level of signa...
Page 20 BD37524FS Technical Note ●Application circuit GND SDA SCL VCC OUTF1 OUTF2 OUTR1 OUTR2 OUTS1 OUTS2 LOUT MUTE GND I2C BUS LOGIC ■Fader Gain:+15d B~-79dB/1d B step ★no pop noise ■LPF ade r★ fc=55/85/120/...
Page 21 BD37524FS Technical Note ●Interfaces Terminal Terminal Terminal Equivalent Circuit Terminal Description No. Name Voltage Vcc A terminal for signal input. The input impedance is 100kΩ(typ). Vcc A termi...
Page 22 BD37524FS Technical Note Terminal Terminal Terminal Equivalent Circuit Terminal Description No. Name Voltage Power supply terminal. 21 VCC 8.5 A terminal for clock input of I2C BUS communication. 22 S...
Page 23 BD37524FS Technical Note ●Notes for use 1. Absolute maximum rating voltage When it impressed the voltage on VCC more than the absolute maximum rating voltage, circuit currents increase rapidly, and th...
Page 24 BD37524FS Technical Note ●Thermal Derating Curve About the thermal design by the IC Characteristics of an IC have a great deal to do with the temperature at which it is used, and exceeding absolute ma...
Page 25 BD37524FS Technical Note ●Ordering part number 7. ±0 .3 Part No. Part No. Package Packaging and forming specification FS : SSOP-A24 E2: Embossed tape and reel SSOP-A24 <Tape and Reel information&gt...
Page 26 Notice No copying or reproduction of this document, in part or in whole, is permitted without the consent of ROHM Co.,Ltd. The content specified herein is subject to change for improvement without not...

Manual Details

Brand ROHM
Pages 26
File Size 520.29 KB
Published June 18, 2026
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Frequently Asked Questions

How does the unit prevent switching noise in volume or gain controls?

It utilizes an 'Advanced switch circuit' to reduce various types of switching noise in inputs like volume, main control, and fader.

What voltages are required for optimal operation?

The specified operating voltage (VCC) range is 7.0 V minimum up to 9.5 V maximum.

Does the processor support various audio input types?

Yes, it features a Stereo 4-input selector and a Differential 1-input selector.

What safety measures must be implemented when using this product?

Users must implement safety measures like derating, redundancy, or fire control to guard against physical injury or damage caused by failure.

Can this sound processor be used outside of automotive systems?

Yes, while optimal for car audio, it can also be used with equipment such as mini Compo, micro Compo, and TVs.