This part is a kind of semiconductor called BD3491FS.

Function of this product has Sound Processor.

Manufacturers : Rohm

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Datasheet Analog Sound Processor series Sound Processor with Built-in Surround Sound Function BD3491FS General Description Built in stereo 6 input selectors and volume that there is not an impedance change of a volume terminal. And this is sound processor can realize 2-band equalizer (Bass/Treble, Gain±14dB / 2dB_step) and BassBoost, Output gain, Surround by external components. Features Equipped with 6 single ended stereo input selectors Built-in input gain controller suitable for mobile audio. Volume input terminal can be used as a microphone input terminal since its impedance remains constant even if volume setting is changed. Bi-CMOS process is suitable for the design of low current and low energy. It also provides more quality for Bi-CMOS small scale regulator and heat in a set. Th [ ... ]

BD3491FS PDF Datasheet Download