OPL3

The Yamaha YMF262, also known as the OPL3 (OPL is an acronym for FM Operator Type-L), is an FM synthesis sound chip released by Yamaha Corporation in 1988. It is an improved version of the Yamaha YM3812 (OPL2C).

The YMF262 improves upon the feature-set of the YM3812, adding the following features:

YMF262 also removed support for the little-used CSM mode, featured on YM3812 and YM3526.

The YMF262's FM synthesis mode was configurable in different ways.

The YMF262 was used in many sound cards, including the popular Sound Blaster Pro 2.0, Sound Blaster 16 ASP and AWE family.

Like its predecessor, the OPL3 outputs audio in digital-I/O form, requiring an external DAC chip like the YAC512.

Yamaha also produced a fully compatible, low-power variant, the YMF289 OPL3-L, which targeted PCMCIA sound cards and laptop computers.

Yamaha's later PC audio controllers, including the YMF278 (OPL4), the single-chip Yamaha YMF718/719S, and the PCI YMF724/74x family, included the YMF262's FM synthesis block for backward compatibility with legacy software. See YMF7xx for more information.

Competing sound chip vendors (such as ESS, OPTi, Crystal and others) designed their own OPL3-compatible audio chips, with varying degrees of faithfulness to the original OPL3. Some manufacturers (namely Avance Logic, now Realtek) reverse-engineered the YMF262 and implemented a near-identical clone in their chips.

In 2015 an open-source RTL implementation of the OPL3 was written in SystemVerilog and adapted to an FPGA.

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