Finally, proper termination of all inputs and outputs must be incorporated into the layout. Unterminated lines, such as coaxial cable, can appear to be a reactive load to the amplifier. By terminating a transmission line with its characteristic impedance, the amplifier's load then appears to be purely resistive, and reflections are absorbed at each end of the line. Another advantage of using an output termination resistor is that capacitive loads are isolated from the amplifier output. This isolation helps minimize the reduction in the amplifier's phase-margin and improves the amplifier stability resulting in reduced peaking and settling times.

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General High-Speed Amplifier Design Considerations

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TOA Electronics THS4130 manual General High-Speed Amplifier Design Considerations