National Semiconductor Corp. introduced what it touts as the industry's first decoder with an integrated 2:1 multiplexing (MUX) video switch that uses analog technology to accurately convert standard and high-definition video (YPbPr) signals to a computer video (RGB) format.
The LMH1251 increases compatibility between different video standards and formats, allowing consumers
to output video directly from DVD players, gaming devices and other devices to their personal computer
monitors. This new product also performs all the necessary sync processing to generate horizontal and
vertical sync signals from standard (SD) and high-definition (HD) video formats.
"Converting signals in the analog domain through National's integrated, all-in-one decoder gets rid of
all the complex external circuitry or additional chips you'd find in a digital solution," said Erroll
Dietz, VP of National Semiconductor's amplifier products group. "Instead, it offers manufacturers an
easy way to add component video compatibility without the headaches and errors of current solutions."
The LMH1251's conversion process is done using analog technology via a color-space conversion matrix,
eliminating multiple stages of digital implementations. The result is a cleaner, crisper, decoded
video image that is superior to alternative approaches that use discrete components, digital products
or FPGAs, said National.
The LMH1251 converts video to within 1 percent accuracy based on vector scope analysis, which exceeds
the accuracy of current solutions on the market. The device accepts one set of YPbPr inputs and one
set of RGB/HSync/VSync inputs. Using the integrated 2:1 MUX and based on the input selected, the
output will be either a decoded TV or buffered PC video signal. The LMH1251's RGB path has 400MHz of
bandwidth, enabling it to accept up to 1,600 by 1,200 UXGA video resolutions. The output displays the
unaltered RGB video signal.
The YPbPr video path has 70MHz of bandwidth. It is equipped with a smart video detection circuit that
automatically senses 480i, 480p, 720p, 1,080i and 1,080p video formats, applying the appropriate
color-space conversion and outputting the video in a RGBHV format. The company added that the LMH1251
eliminates the need for a microcontroller to choose the proper detection scheme and also saves board
space by integrating all the necessary components: a sync processor, a 2:1 MUX and an analog
color-space conversion matrix.
Available in a TSSOP-24 package, the LMH1251 is priced at $3.49 in 1,000-unit quantities. Pb-free
package options are also available.