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Sound Processor ICs for Car Audio

Key Feature 1 | Key Feature 2 | Key Feature 3 | Key Feature 4 | Lineup

Expanded lineup: 18 models

Overview

Car audio systems require high fidelity. ROHM Ics offer a wide dynamic range, low distortion, and low noise, making them ideal for a wide variety of car audio systems.
ROHM utilizes analog technologies for the lowest noise and distortion on the market. The BD375 series is comprised of 18 models in different input/output channels and tuning functions for compatibility with different audio sources, cabin interiors, entertainment systems, and customer preferences. In addition, original advanced switching technology is employed to minimize shock noise during volume switching, ensuring high fidelity operation.

 SSOP-A20,SSOP-A24,SSOP-B28,SSOP-A32
Select the ideal sound processor from our broad lineup, from standard products to high performance models

Features

  1. Advanced switching technology utilized to minimize shock noise during volume/tone/fader adjustment.
  2. No external parts required. Microcontroller-controlled 2-/3-band equalizer built in
  3. Internal loudness function enables audio adjustment based on cabin characteristics.
  4. Integrated subwoofer LPF
  5. Ground isolation amp input built in for high common mode rejection ratio: 65dB (typ.)
  6. Total harmonic distortion: 0.001% typ.
System Block Diagram
System Block Diagram

Lineup

Lineup

Key Feature 1 : Advanced switching technology eliminates shock noise for high fidelity adjustment

With conventional volume technology the signal waveform becomes momentarily disconnected during adjustment, resulting in shock noise. (Refer to the blue line in the figure at right)
ROHM's advanced switching technology eliminates these instantaneous disconnections, smoothing out the signal waveform during adjustment for virtually no shock noise. (Refer to the red line in the figure at right)
The BD375 series utilizes proprietary switching technology not only for volume, but for input gain adjustment, tone control, and loudness switching as well.		 Waveform Comparison During Volume Switching

Key Feature 2 : Ultra-low loss and distortion for high fidelity audio

The development of high performance internal elements circuitry results in low noise, low distortion sound processors (3.8uVrms slew noise at 0dB input/output gain and 0.001% distortion at 1Vrms input). This ensures high fidelity audio reproduction in automotive systems.
BD375Series Distortion

Key Feature 3 : Integrated 2-/3-band parametric equalizer

Until now changing the gain of the equalizer and the target frequency required modification of the external components. ROHM's novel circuit design with integrated programmable parametric equalizer enables the target frequency (fo), equalizer gain, and Q Curve to be controlled via microcontroller without the need for external parts/modifications. Parametric Equalizer Frequency Characteristics

Key Feature 4 : New parametric equalizer for loudness

Vehicles come in all types of shapes and sizes. In order to create a realistic sound stage with high fidelity audio bass correction (utilizing LPF, HPF, and loudness, for example) is required.
ROHM has developed a parametric-type loudness function for low-end (bass) correction compatible with vehicles of all types. Control is enabled using a microcontroller via I2C bus. In addition, the target frequency and high-end gain can be freely adjusted, making bass correction possible without requiring external components.
Fo Frequency Characteristics   Hicut Frequency Characteristics

Lineup

Sound Processors with Built-In 2-Band Equalizer

Part No. Power
Supply
Voltage
(V)		 Current
Consumption
(mA)		 No. of Input
Selectors		 Input
Gain (dB)		 Volume
(dB)		 Fader (dB) Para-metric
EQ		 Loudness LPF for
Subwoofer		 Output
Noise
(µVrms)		 Maximum
Output
(Vms)		 Distor-tion
(%)		 Package No. of
Outputs
Single ISO
7511FS 7.0
to
9.5		 15 3 0 0
to
+20		 0
to
-40		 0
to
-62,
∞		 4 - - - 6 2.3 0.005 SSOP-
A20
BD37512FS 1
BD37513FS 38 +15
to
-79,
∞		 0
to
-79,
∞		 ○ 3.8 0.001
BD37514FS 5 ○
BD37515FS +15
to
-79,
∞		 ○ ○
BD37521FS 0
to
-79,
∞		 4 - EXT - SSOP-
A24
BD37522FS 4 ○ ○
BD37523FS +15
to
-79,
∞		 5 ○

Sound Processors with Built-In 3-Band Equalizer

Part No. Power
Supply
Voltage
(V)		 Current
Consum
ption
(mA)		 No. of
Input
Selectors		 Input
Gain
(dB)		 Vol-
ume
(dB)		 Fader
(dB)		 Para-metric
EQ		 L
o
u
d
n
e
s
s		 LPF for
Sub-woofer		 Mixing L
e
v
e
l

M
e
t
e
r		 O
p
t
i
o
n
s		 Output
Noise
(µVrms)		 Maximum
Output
(Vms)		 Distor-
tion (%)		 Pack-
age
Single I
S
O		   No. of
Out-puts		   A
T
T
BD37524FS 7.0
to
9.5		 38 4 1 0
to
+20		 +15
to
-79,
∞		 +15
to
-79,
∞		 6 ○ ○ LPF - - ○ - 3.8 2.3 0.001 SSOP- A24
BD37531FV 2/3/5 3/2/1 - - SSOP- B28
BD37532FV LPF
BD37533FV ○  
BD37534FV ○
BD37541FS EXT - - - SSOP-
A32
BD37542FS LPF ○
BD37543FS LPF
+
HPF		 ○
BD37544FS 1/3/4 - - Super
Bass
BD37545FS 2/3/5 ○ Ext.
I/O

*The input selector (i.e. 2/3/5 and 3/2/1) indicates the possible recombinant single and ISO inputs

ROHM utilizes and cultivates the most advanced technologies to develop products optimized to meet customer needs.
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