This part is a kind of semiconductor called BD37534FV.

Function of this product has Sound Processor.

Manufacturers : ROHM

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Datasheet Sound Processor with Built-in 3-band Equalizer BD37534FV General Description BD37534FV is a sound processor with built-in 3-band equalizer for car audio. A stereo input selector is available that functions to switch single end input and ground isolation input, input-gain control, main volume, loudness, 5ch fader volume, LPF for subwoofer and mixing input. Moreover, “Advanced switch circuit”, which is an original ROHM technology, can reduce various switching noise (ex. No-signal, low frequency like 20Hz & large signal inputs). Also, “Advanced switch” makes microcomputer control easier, and constructs a high quality car audio system. Features  Reduced switching noise of input gain control, mute, main volume, fader volume, bass, middle, treble, loudness by using advance [ ... ]

BD37534FV PDF Datasheet Download