Creative MuVo Slim: flashy mixed-signal music

The MuVo design takes advantage of a highly integrated MP3 ASIC and builds additional audio goodies into the credit-card-sized player. An FM StereoTuner with 32 presets, and the ability to record radio or voice to the internal storage makes the MuVo an audio wonder of sorts, considering the size and sub-$100 price. In a further gesture to flexible function, the Slim can act as a mass storage device for data files beyond just your tunes.

The heart of the MuVo Slim is the mixed-signal SMTP3510B ASIC, crafted by Sigmatel specifically with the task of flash-based MP3 player in mind, Figure 2.

The Sigmatel part supports digital audio processing to decode the compressed music files and contains the necessary CODECs to translate expanded digital files into high-quality stereo audio output. On top of the audio basics for playback, the SMTP3510 implements the MuVo’s five-band custom equalizer with four presets.

To deliver a true system-on-chip to Creative, and the many other MP3 competitors who use this part, Sigmatel included a healthy mix of other digital and analog blocks in the monolithic ’3510 chip. A microcontroller and associated digital circuits manage user input, directly drive the monochrome 132 x 32 STN LCD, and implement a high-speed USB 2.0 interface for file transfer.

Analog add-ons include an A/D converter, used here to digitize and record either the microphone input or the FM radio feed from Philips TEA5767 single-chip FM tuner, itself a slick piece of audio silicon design which also supports real-time radio in the Muvo Slim.

DC/DC-conversion and other power management reside on-board the Sigmatel part, though a separate Linear Technology Corp Li-Ion charge management chip (LTC4053) is used for the internal—but replaceable—rechargeable cell. High-voltage AC drive for the electroluminescent LCD backlight is also a specialty task, in this case left to a Citizen Electronics ELD-4410 lamp driver. Two LDO local regulators from Texas Instruments and Fairchild Semiconductor round out power management in the Slim.

As the Creative MuVo design demonstrates, devices like the ‘system-on-chip’ Sigmatel ASIC may not ever get to truly single-chip audio systems, but this one sure gets close, providing the backbone for compact, affordable, and low-power players. When it comes to mixed signal design, it’s amazing what a laser focus on the end product can do to help deliver a home run chip.

About the author
David Carey is President of Portelligent, www.teardown.com. The Austin, Texas company produces teardown reports and related industry research on Wireless, Mobile, and Personal Electronics.