Inside the Apple iPod Design Triumph

Steve Jobs is recognizably the top cheerleader for Apple's products. And the inventor of such hyperbole as "insanely great" has not abandoned that characteristic for the company's iPod MP3 player.

"With iPod, Apple has invented a whole new category of digital music player that lets you put your entire music collection in your pocket and listen to it wherever you go," the Apple CEO said when he introduced the product in October 2001. "With iPod, listening to music will never be the same again."

Although no one could accuse Apple, let alone Jobs, of being shy about product promotion, it's a different story when it comes to its engineering and building processes. The company has always been tighter lipped than the Pentagon when it comes to releasing design chain details.

But that hasn't prevented some companies from satisfying their curiosity about what's inside the advanced MP3 player. Some serious reverse engineering and discussion within the electronics industry unearthed unusual details of Apple's development process.

It turns out that much of the underlying iPod design was performed by outside companies. The Cupertino folk haven't given up on their heritage of design excellence—they're just bowing to some inevitable directions in consumer electronics by borrowing from established experts linked together for what may be the first design chain for the iPod.

A Unique Design Chain Approach
Realizing that the MP3 market was still in its infancy, Apple developed a layered design chain tuned for an early-stage market to create the iPod. Even more unusual for Apple, it relied on a platform and reference design created by a third party, PortalPlayer, of Santa Clara, Calif. Founded in 1999, PortalPlayer has a stellar cast of Silicon Valley executives and investors, including renowned venture capitalist Gordon Campbell.

PortalPlayer had developed a base platform for a variety of audio systems, including portable digital music devices, general audio systems and streaming audio receivers. It appears that Apple picked PortalPlayer because its design expertise yielded the highest quality of sound, according to industry sources.

Because of the unusually restrictive nondisclosure agreements in place among Apple, PortalPlayer and other members of the sub-design chain, key officials were not able to directly comment on their work with Apple. However, some members of the subchain provided Electronics Design Chain Magazine with a glimpse inside the iPod core.

Once Apple and PortalPlayer became design chain partners, PortalPlayer then selected other design chain members and managed the design process. Four key criteria were behind the selection of other members of the design chain, none unusual for a consumer electronics product:
• highest quality sound
• off-the-shelf components
• cost
• time to market
Under the Hood
The trail to find iPod's design chain starts with some reverse engineering of the device by Portelligent Inc., an Austin, Texas, firm providing product and technology intelligence for consumer electronics companies.

"First and foremost, the product was elegantly designed in classic Apple fashion," says David Carey, president of Portelligent. "They did product design from the outside in." Carey says the company had a vision of what the player should be and what it should look like. The subsequent design parameters were dictated by its appearance and form factor.

That outside-in perspective helped determine a number of the components, including the planar lithium battery from Sony and the 1.8-inch Toshiba hard drive, which is the only company presently manufacturing that form factor. The essential units—battery, hard drive and circuit board—are layered, one atop the next.

"It was very thoughtful layering and nesting of the components mechanically," Carey adds. "There's not a lot of unused volume inside [the iPod]."

The rest of the device uses a dedicated MP3 decoder and controller chip from PortalPlayer, a Wolfson Microelectronics Ltd. stereo digital-to-analog converter, a flash memory chip from Sharp Electronics Corp., a Texas Instruments 1394 firewire interface controller, and a power management and battery charging IC from Linear Technologies Inc.

What Apple conspicuously did not do is use an ASIC or other custom chip to integrate all the functions it needed onto one piece of silicon, which would have presumably saved space and battery life.

"Like with many of the systems being done today, it has time-to-market and risk-management issues," Carey notes. When a company moves to a custom system-on-chip, "you run the risk of a design flaw, and it's far cheaper to buy the best [components]."

PortalPlayer's vice president for marketing, Michael Maia, can't publicly disclose why Apple and PortalPlayer decided not to use an ASIC or discuss other aspects of the iPod design, but his description of a generic systems customer in the marketplace could be considered applicable to Apple.

"There's a range of customers out there, from an OEM that does all its own design internally to the right-hand side that do all their design through ODMs [original design manufacturers] in Asia," Maia says. "There are guys in the middle who may specify the product down to the semiconductor level and then have the ODM build it."

PortalPlayer decided to develop a reference model for a high-quality portable audio player based on a standard product design strategy. It developed a series of designs that enabled customization, and at the same time provided a stable environment, thereby eliminating the need to start design from scratch.

PortalPlayer's Winning Relationships
Part of PortalPlayer's design chain strategy is to offer development tools as well as to form relationships with third parties that offer other capabilities. The result is a series of reference designs for different applications along with roadmaps for current and future application capabilities.

"Customers can get access to that, and in that, we work very closely with select partners that we have carefully chosen for a host of reasons," says Maia. "Wolfson [for example] has what our minds and ears tell us are excellent quality codecs."

In addition, "Wolfson has excellent quality technology and a good price point," he notes. As a result, PortalPlayer and Wolfson Microelectronics became design chain partners for the audio player reference design.

The design process was a matter of a few months of iterative loops. PortalPlayer would use the Wolfson silicon in a prototype circuit, then go back to the Edinburgh, United Kingdom, company with any problems. "Once you've tried the device, we can hone in on the issues," says Julian Hayes, vice president of marketing at Wolfson. "We're fairly expert at solving problems these days."

PortalPlayer selected Linear Technologies of New York City for the power management because its technology is leading edge and also because there were preexisting ties between upper management of the two companies.

But PortalPlayer had to develop a working relationship with TI, a competitor in other areas, because Apple insisted that the Dallas-based company provide the 1394 chip.

The flash memory from Sharp, of Mahwah, N.J., shows a different relationship, as PortalPlayer considers itself "agnostic" when it comes to memory chip vendors.

Risk Reduction

Using a platform like PortalPlayer's, in which systems are designed and chip designs verified, offers fewer worries to a company that is in a rush to market. With the design chain approach it has taken, Apple avoided the technical challenges of integrating DRAM and logic processes.

"To do everything in one part is a complex, risky and potentially costly alternative to integration of available components at the electronic assembly level," Carey says. Certainly, custom work can offer cost reductions in large volume, but there are two countering considerations for a company like Apple.

One would be volume, according to Mike Paxton, senior analyst of converging markets and technologies at Scottsdale, Ariz.-based In-Stat/MDR.
"If you listen to Steve Jobs, he said they sold 125,000 in the fourth quarter [of 2001], which is impressive," given that the iPod only began to ship in October, Paxton says. By checking that figure against discussions with component suppliers, he decided that it was probably accurate. But while such sales, if kept constant for an entire year, would make Apple the second- or third-largest MP3 player manufacturer worldwide, the volume is small compared to more common uses of custom chips.

In addition, the IC costs for a device like the iPod won't dominate Apple's bill of materials. Carey estimates that the hard drive is at least 50 percent of the expense, so the advantage of bringing design in house or working with a single chip vendor instead of a more extensive design chain using a variety of outside suppliers is reduced.

The other consideration is the typical trade-off when doing custom work: flexibility in design and vendor selection versus the potentially low volumes and relatively high unit prices.

All for One
Apple's design chain relied on off-the-shelf components integrated in an elegant way. Even critical pieces such as the digital-to-analog converters (DAC) are off-the-shelf discrete devices. The DAC "is a standard component that was designed for Wolfson for portable music players," says Hayes. The Toshiba drive is another standard part.

"With iPod, Apple has invented a whole new category of digital music player that lets you put your entire music collection in your pocket and listen to it wherever you go." Steve Jobs, Apple Computer

Where the value rapidly accumulates is in the intelligent coordination among the vendors and integration of their products. The combination and linkage of the DAC to other components is where the PortalPlayer-Wolfson design chain provided real worth. "There's a lot of embedded stuff" inside the design, says Hayes. "It has some fairly complex DSP algorithms to enable the features of the products that Apple may or may not be taking advantage of."

Apple and PortalPlayer also relied on other key design chain partners. While the Toshiba drive, for example, uses a standard AT interface, the connector is a custom design. And it appears Apple relied on Toshiba for guidance about heat dissipation and shock tolerance.

The nondisclosure agreement between Apple and Toshiba precludes the disk drive maker from describing its design chain role. However, a source close to the design chain says Toshiba did contribute to the overall design.

Don't Count Apple Out

It would be a huge mistake to assume that all the design work happened elsewhere and that Apple had no substantial input. A reference design is far from having a finished product, even electronically. The ultimate circuit design was still Apple's, as far as any outsider can tell.

"The value is putting it all together and optimizing the design to eek out the best performance, get the best power utilization, the best audio performance," says Wolfson's Hayes. "That is not a trivial task by any means. Sometimes it's very difficult in a cost constrained [situation] and small form factor to get the performance." Factors that can influence the final sound can be the circuit board layout, the circuit design itself, the handling of the power supply and the overall implementation.

"It's a combination of all those things that create that high-quality performance," Hayes adds.

In his opinion, and in that of many reviewers, Apple hit a home run. "Certainly I think it's about the best audio quality we've come across for that type of product in the marketplace in terms of intrinsic audio quality and delivered audio quality," Hayes says.

Then there is the user interface design, which has received strong reviews for the implementation of a 1394 interface for music downloads so fast that it could make your head spin. And it's easy to use.

"It's a fantastic user interface," emphasizes Hayes. "It's by far and away the best user interface of any product of this type. It sets it apart from any of the other comparable MP3 players of its ilk."

Choosing a development platform allowed Apple to focus on its true genius for form factors and user interfaces. "Those two are Apple's strengths," says Vinay Asgekar, director of research for semiconductor and high tech at Boston-based AMR Research. "Apple knows how to make a high-tech product consumer friendly. That has been its core strength from the introduction of the Apple Macintosh. That could be its strategy for iPod."

Troubled Waters
With all the positives, is there a down side?

"Managing that activity [among multiple partners] becomes extremely difficult," says Asgekar, as projects become harder to coordinate. "You have to make sure your supplier's development and marketing roadmaps match up with your development and marketing roadmaps."

While PortalPlayer's Maia is restricted from discussing how Apple managed its iPod design chain, he was able to describe how systems houses in general work with the audio subsection designer. A drawback for Apple, and other systems houses relying on reference designs, is protection of its product and market space. When fundamental parts of the design are done by others, there is an almost certainty that competitors will eventually ship products using the same basic technology. Obviously, a company like PortalPlayer makes the same silicon, firmware, tools and reference designs available to many other companies.

While PortalPlayer provides designs on an exclusive basis for some customers, Maia hints that the guts of the iPod may appear in other devices soon. So although Apple has been the first of PortalPlayer's customers to ship products using the platform, many more are slated to introduce their own offerings by this summer.

No doubt subsequent versions of the iPod will yield a revised design chain as different components and optimizations are discovered and needed. But for now, Apple's first design chain strategy and product have been a success.


Erik Sherman writes about business and technology for such publications as Newsweek, US News and Technology Review. Reach him at esherman@designchain.com.

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