Neil Edward



  • Telecom Switchable Termination Networks

  • Created: Apr 28, 2016

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The impedance-matching of transmission lines is an important parameter that minimizes loss of signal. This switchable line-terminating impedance features ±2.5% resistance accuracy over extended temperature range with input voltage range from -3.6V to +3.6V. The supply current maximum is 50uA and termination option of 100Ω and 120Ω.

This design circuit is comprised of primary and secondary terminating device. The primary terminating device is MAX3408EUK+T switchable termination network impedance that is designed to change the termination value of a line. The specified for operation power supply is +4.5V to +5.5V while the temperature range is -40°C to +85°C. The secondary terminating device is DS2155GN software-selectable T1, E1, or J1 single-chip transceiver in which it functions in transmission by correcting source impedance and generation of waveshapes, while in reception it provides secondary termination and recovers clock and data from the network.

The design is applicable to different types of application in telecom networks that meets its required termination impedance. It can be used for testing and typical termination related to coaxial or twisted pair. It is also applicable to industrial networks, video security, and data routers.