Inner Workings: Inside a Video iPod
With its eye-catching design and seamless integration with the iTunes Music Store download service, Apple's iPod has taken the portable-music market by storm. But once you get beyond the iPod's distinctive, sexy styling and crack open its case, you'll find a collection of off-the-shelf components not all that different from those used in other personal media players. Since its debut in the fall of 2001, the iPod has gone through several versions, but Apple's remained loyal to its primary suppliers, such as PortalPlayer, which developed the reference CPU/audio processor; Wolfson Microelectronics, which makes the audio codec; and Toshiba, which supplies the hard drive.
Pry off a video iPod's cover (caution: doing so voids the warranty), and you'll see there's not much unused space in the device's well-thought-out internal layout. Looking at the exposed iPod from the front, you'll see a super-slim 2.5-inch TFT (thin-film transistor) LCD, the distinctive click-wheel controller, and a printed circuit board. (The video iPod's LCD is encased in a clear resin rather than placed behind a plastic cover, as it was on older models.) Lift up the click wheel and you'll see the chips and memory modules attached to the circuit board.
A Linear Technologies battery charger and power-management system sit at the circuit board's upper left corner.
In the upper right-hand corner is the Wolfson audio codec, which sends audio to the headphone jack, while the firmware flash module and step-down switching regulator (which handles input voltage swings) are packed in the lower right corner.
Looking at the back of the circuit board - once you remove Toshiba's compact 1.8-inch 30-GB or 60-GB hard drive - you'll see the two chips that serve as the video iPod's heart and brain. A PortalPlayer microprocessor features two ARM-based cores and audio processing, while a Broadcom VideoCore mobile video processor/decoder supports both MPEG-4 and H.264 video at a maximum resolution of 480 x 480. (The LCD has a 320 x 240 resolution, but the iPod's video can be displayed on a TV.) Also on the motherboard are a 256-MB Samsung SD RAM chip, the click-wheel controller, and a power-management unit. The rechargeable battery and the headphone jack are both mounted on the metal backplate.
As the iPod evolves, it's possible some significant changes will be made, particularly to its media processors. Reportedly, PortalPlayer, Broadcom, and Samsung are all vying to supply Apple with a device that will combine all audio and video processing and decoding in a single chip.