It is an eight-channel PCM/ADPCM sample-based synthesizer designed for use with video game machines, packaged in a 64-pin QFP.
The YMZ280B can either use an internal crystal oscillator running at 16.9344 MHz or be connected to a master clock line.
The chip can be connected to up to 16 MB of external memory to provide the voice data for sound reproduction.
The sound data can be encoded as 4-bit ADPCM, 8-bit PCM, or 16-bit PCM, played back in a wide range of frequencies (up to 256 steps), and then mixed together and output as a two's complement MSB-first digital data stream meant to be connected to a complementing DAC chip like the YAC513.
The YMZ280B can also be connected to a YSS225 effects processor (EP), allowing two of the 8 channels to be processed further.