NATIONAL INTEGRATES ANALOG SIGNAL PATH FOR CCD IMAGING IN GREYSCALE AND COLOR SCANNERS

• Pixel-to-Pixel Analog Gain Correction Preserves Dynamic Range
• Correlated Double Sampling Assures Precision Offset Correction
• Performs All Digital Timing & Control
• Compatible With Wide Range of CCDs
• Integrated Solution Improves Picture Quality And Reduces System Cost

SANTA CLARA, CA., September 18, 1995 -- A highly integrated sensor processor that performs all the analog functions necessary for CCD sensor operation was introduced today by National Semiconductor. The device, called LM9800, is compatible with greyscale and color CCD sensors used in sheetfed and flatbed scanners.

"Based on our initial experience with imaging partners, we're now able to replace as many as a dozen components with this single device, saving both board space and system cost," said Steve Null, National's product marketing manager. "Mixed-signal system level products, such as the LM9800, will continue to offer customers the additional flexibility, resolution and signal quality they need to design scanners into applications that have yet to be imagined."

The LM9800, which offers 8-bit resolution and operates at a 2.5 million pixel/second conversion rate, removes errors from and digitizes a linear CCD pixel stream, while generating all the necessary clock signals to drive the CCD. An internal configuration register sets CCD and sampling timing to maximize performance and simplify the design. With the ability to adjust all of the CCD timing signals, designers can quickly adapt to different types of CCDs without sacrificing time-to-market.

Among the LM9800's integrated functions are correlated double sampling for black level and offset compensation resulting in minimum noise and offset error; 8-bit analog-to- digital conversion; and pixel-by-pixel gain adjust that maximizes the dynamic range and resolution, even on "weak" pixels.

A95004DA

Lit# 108312-001