Under the Hood of Fuji's A330: Analog links to digital pictures - Embedded.com

Under the Hood of Fuji’s A330: Analog links to digital pictures

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The high end of any market usually gets the buzz, but it’s the low end that usually gets the buyers. Consumers can now buy entry-level digital still cameras (DSCs) that perform like yesterday’s high-end device, and the $150 3Mpixel/3X zoom Fujifilm A330 packs a punch for the money.

Responding to cost pressures, DSC makers have looked to highly-integrated digital camera engines, falling memory costs, and expanding sensor capabilities to keep price down and function up. Despite the impressive digital side of the DSC coin, however, imaging begins in an analog world and a host of mixed-signal issues must be tackled.

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Looking at the A330’s CCD image sensor from Matsushita (#MN39480), we see reductions in pixel size which lower sensor cost and bring quite usable resolution to the mass-market. Outputs from the CCD pass on to the Renesas #HD49334 CCD analog front-end (AFE), a highly specialized part which manages gain (exposure), correlated double sampling (noise reduction), and analog to digital signal conversion. A mixed-signal part from Fuji (#MD2174) orchestrates the precise timing and readout of signals from CCD to AFE.

Before images are captured, a rather amazing control loop between sensor, image processor, and optics properly sets zoom, focus, shutter, and iris in the lens assembly— a task left in this case to the Renesas #M50239 multi-channel motor driver. The Processor Board also supports a power control ASIC (#AN30202A) from Matsushita, likely responsible for the often-complex CCD bias voltages.

To modularize the core image-processing electronics for re-use in other camera models, the smaller A330 Processor Board plugs in orthogonal to the larger Main Board. While seemingly counter to camera thickness reduction, the board height is matched to the lens module thickness such that camera dimensions are not compromised.

Consistent with the highly competitive entry-level DSC market, our cost analysis for the A330 suggests very tight end-margins. But competition is giving the consumer great deals, and significant analog content is still a must to deliver image quality along with low price.

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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) .

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