GS6042 Datasheet, PDF (16/21 Pages) Semtech Corporation – 6G UHD-SDI/3G/HD/SD Adaptive Cable Equalizer

5. Application Information
5.1 High-Gain Adaptive Cable Equalizers
The GS6042 is a multi-rate Adaptive Cable Equalizer. In order to extend the cable lengths that
the device can support, it is necessary to have high-gain in the equalizer.
In particular, an SDI video cable equalizer must provide wide band gain over a range of
frequencies in order to accommodate the range of data rates and signal patterns that are
present in a SMPTE-compliant serial video stream.
Small levels of signal or noise present at the input pins of the equalizer may cause chatter at
the output. In order to prevent this from happening, particular attention must be paid to
board layout.
5.2 PCB Layout
Special attention must be paid to component layout when designing serial digital interfaces
for HDTV and other high-speed video applications.
An FR-4 dielectric can be used, however, controlled impedance transmission lines are required
for PCB traces longer than approximately 1cm. Note the following PCB artwork features used
to optimize performance:
• PCB trace width for high data rate signals should be closely matched to SMT component
width to minimize reflections due to changes in trace impedance
• High-speed traces should be curved to minimize impedance changes
• Cutouts in the inner layers should be used under the GS6042 input and output
components to minimize parasitic capacitance
GS6042
Final Data Sheet
PDS-060055
Rev. 3
May 2014
www.semtech.com
16 of 21
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