The February 2023 issue of IEEE Spectrum is here!

Close bar

Chip Hall of Fame: Micronas Semiconductor MAS3507 MP3 Decoder

This chip began the digital music revolution

1 min read
Micronas Semiconductor MAS3507 MP3 Decoder
Eirik Solheim

Before the iPod, there was the Diamond Rio PMP300.

Not that you'd remember.

Launched in 1998, the PMP300 became an instant hit, but then the hype faded faster than Milli Vanilli. One thing, though, was notable about the player. It carried the MAS3507 MP3 decoder chip—a RISC-based digital signal processor with an instruction set optimized for audio compression and decompression.

MAS3507 MP3 Decoder

Manufacturer: Micronas Semiconductor

Category: Amplifiers and Audio

Year: 1997

The chip, developed by Micronas (now TDK-Micronas), let the Rio squeeze about a dozen songs into its flash memory. This is laughable by today's standards, but at the time it was just enough to compete with portable CD players, which suffered from a tendency to skip if jostled. The Rio and its successors paved the way for the iPod, and now you can carry thousands of songs—and all of Milli Vanilli's albums and music videos—in your pocket.

diagramAs this Micronas design document shows, the MAS3507 was built around doing only one thing well—decoding MPEG Audio Layer III data, a.k.a. MP3 files. Originally developed simply as the storage subsystem for holding the soundtrack of MPEG videos, the MP3 format took on a life of its own.Image: Micronas

The Conversation (0)

How Ted Hoff Invented the First Microprocessor

Hoff thought designing 12 custom chips for a calculator was crazy, so he created the Intel 4004

14 min read
How Ted Hoff Invented the First Microprocessor

The rays of the rising sun have barely reached the foothills of Silicon Valley, but Marcian E. (Ted) Hoff Jr. is already up to his elbows in electronic parts, digging through stacks of dusty circuit boards. This is the monthly flea market at Foothill College, and he rarely misses it.

Ted Hoff is part of electronics industry legend. While a research manager at Intel Corp., then based in Mountain View, he realized that silicon technology had advanced to the point that, with careful engineering, a complete central processor could fit on a chip. Teaming up with Stanley Mazor and Federico Faggin, he created the first commercial microprocessor, the Intel 4004.

Keep Reading ↓Show less