Circuit Protection of Video in/out
Design Notes:
Protection Application:
The video signals used in S-video and Composite video formats vary between 0.5 and 2.0Vp-p, with a maximum frequency of 5MHz. At this frequency, the capacitance of the suppressor needs to be taken into account. The signal lines to be protected from ESD include Luminance and Chrominance for S-video, and the single conductor for Composite video.
Solution Description:
As shown at the left, discrete multilayer varistors are recommended for protection. Due to the analog nature of the video signals, uni-polar TVS diode arrays are not recommended as the may clip the negative part of the video signal.
Companion Solutions:
Other solutions within the Ruilon MLV portfolio exist in addition to these recommendations. For example, if the manufacturing process cannot handle 0402-size components, devices with the same characteristics can be found in 0603-size components.
Regulatory Issues:
The IEC 61000-4-2 will be the most appropriate standard that applies for this port. It supplies a test method for verifying that the end product is not susceptible to ESD events.
Unique Features:
Does not apply.
Application Warnings:
The F-type connector shown at the left is specifically for set top box-to-monitor video circuits. If the F-type connector is for CATV or Satellite inputs, then lightning surges become a concern and MLVs cannot be used. In this case, GDTs are required. See the page on CATV and Satellite inputs for more details.

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