ROHM BH3857AFV Datasheet

Audio ICs

Audio sound controller

BH3857AFV

The BH3857AFV is a signal-processing IC for controlling audio quality in CD radio-cassette players and mini-component
stereo systems. Three-line serial control is available making it easy to adjust tone and volume using a microprocessor.

Applications
Mini-component stereo systems, CD radio cassette play­ers, car audio systems and TVs.

Features

1) Volume (main volume) and tone (bass and treble)
control possible by direct serial link to a microproces­sor. DC control is also possible.

2) Volume control is done with a low-distortion, low­noise VCA, and step noise is suppressed.

3) The gain of the input amplifier can be adjusted, and
two surround matrixes are available to expand the
sound.

4) The IC includes a stable reference voltage source
and input buffer to reduce external component re­quirements, and comes in a compact 40-pin SSOP
package that is perfect for compact designs.

5) Four open-collector outputs are provided to make
logic control possible.

Absolute maximum ratings (Ta = 25C)

Recommended operating conditions (Ta = 25C)

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Audio ICs BH3857AFV

Block diagram

Control of volume, bass, treble and surround 2 can also be done by external application of a DC voltage to the VC (volume), BC (bass), TC (treble) and SC
(surround 2) terminals.
The impedance of the VC, TC, and BC terminals is 10kΩ (Typ.).
The impedance of the SC terminal is 200kΩ (Typ.).

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Audio ICs BH3857AFV

Pin descriptions

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Audio ICs BH3857AFV

Electrical characteristics (unless otherwise noted, Ta = 25C, VCC = 8V, f = 1kHz, BW = 20Hz to 20kHz,

VOL = MAX, Tone = ALL FLAT, R

g = 600Ω, RL = 10kΩ, INPUT_AMP_GAIN = 0dB)

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Audio ICs BH3857AFV

Measurement circuit

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