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I have an LVDS differential 100OHM signal which I want to convert to a single-ended 50 OHM signal. I want to use a BALUN for this conversion.

What kind of BALUN should I use here?

Some BALUNs have 1:1 conversion ratio. Some have 2:1 impedance conversion ratio.

Thanks

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  • \$\begingroup\$ Since your impedance ratio is 2:1 why do you even have to ask the question? \$\endgroup\$ – Brian Drummond Jan 7 '18 at 11:49
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    \$\begingroup\$ The 100OHM LVDS signal connects to two terminals of the BALUN. If we consider the differential signal as two 50 OHM signals than in my reasoning I should use a 1:1 balun. However in some designs I have seen a 2:1 balun used as well. I am looking for a more clear answer. \$\endgroup\$ – user1175197 Jan 13 '18 at 7:38
  • \$\begingroup\$ Also note that your selection of balun will be influenced by the driving frequency of the LVDS. Most often I have seen them made to work at 400Hz or 50/60 Hz some modern smaller units may be higher. The magnetics are not all the same. \$\endgroup\$ – KalleMP Dec 4 '18 at 12:28
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A 100 ohm diff signal is essentially 2 x 50 ohm single ended signals (I know that's a very same analogy).

In the past ive connected one end of the differential signal to the receiver with a 50R series resistor, and the other end terminate with 100R to GND.

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