Sporting an extraordinarily thin body style for a 3X optical zoom digital camera, the Minolta Dimage X uses a vertically-oriented lens train and a right-angle mirror to bury the size of thickness-killing optics inside the case. Light entering at top of the camera is directed by a prism downward through the lens system to the CCD sensor at the bottom, allowing the camera profile to remain at a slim 21mm even when the camera is on and optics are in motion.
Implementation of the unconventional design relies on the usual digital processing and storage but starts with analog technology. A 2-megapixel CCD from Sony (#ICX284AK) captures the image in analog form, and because of space constraints, the CCD is the lone electronic component married to the lens. To insure signal fidelity between sensor and the main board which holds the analog front end, an amazing array of miniature coax cables shield signals line-by-line to keep noise at bay on the low-level CCD signals. About a quarter of the camera volume is occupied by the optics and coaxial cables connecting the CCD Sensor Board to a second small board that plugs into the Main Board.
Once CCD signals arrive at the main board, an Analog Devices analog front end chip (#AD9848) performs 10-bit A/D conversion along with gain (exposure) control, noise reduction, and signal readout timing. A Sony CXD3400N also supports CCD clocking functions. After signal conditioning and digitization, raw image data is processed in a Sanyo DSP, which is supported by a Fujitsu SPARClite microprocessor and Hitachi SDRAM. A 2MB Fujitsu flash memory (#MBM29LV160TE90) holds system operating code. The 1.5-inch color TFT LCD monitor is interfaced to the system via a Sanyo #LV4137 LCD Display Driver and Rohm's #BH6406FV provides support for analog audio input/output.
Returning to the optics, several functions must be performed to manage the lens train and optical exposure. A Sanyo #LB8649 and Rohm #BA6238AN provide drive voltages and analog smarts to deal with zoom motor, focus motor, and aperture (iris) voice-coil elements embedded within the up-ended optics assembly.
Estimated Cost-of-Goods-Sold (COGS) for the Dimage X is less than half of the $399 price. Electronics integration continues to reduce camera form-factor and cost though a clear partitioning of digital and analog functions suggests little technical or economic benefit from combining disparate functions into a common IC process. Sometimes the road less-integrated provides an optimum balance of function, design risk, and cost, particularly when it comes to mixed-signal systems.
David Carey is President of Portelligent. The Austin, Texas company produces teardown reports and related industry research on Wireless, Mobile, and Personal Electronics. (www.teardown.com)