Note: YM2151 is not anything to do with Sega 8-bit consoles, but it is related to the VGM format. The following is transcribed from scans of the YM2151 User's Manual found at

Outline of Functions and Features

Outline of Functions

The YM2151 is an FM-type sound generator equipped with an 8 bit bus line and capable of producing superb audio quality via a microprocessor program. When this IC is used in tandem with the specially-developed YM3012 D/A converter, you can obtain 8-note, left-right/2-channel audio signals.

In addition, this unit is equipped with noise, vibrato, an amplitude modulation circuit, a sound effects circuit, and timer.

The package is a 24-pin dual in-line package.


Summary of the Principles of FM-type Sound Generation

Construction and Features

Block Diagram


Phase Generator

FM Operator

Envelope Generator

Noise Generator

Low Frequency OSC



Pin Wiring

Pin Functions

Device Specifications

Maximum Ratings

Electrical Characteristics


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