3
\$\begingroup\$

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

What kind of BALUN should I use here?

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

\$\endgroup\$
4
  • \$\begingroup\$ Since your impedance ratio is 2:1 why do you even have to ask the question? \$\endgroup\$
    – user16324
    Jan 7, 2018 at 11:49
  • 2
    \$\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\$ Jan 13, 2018 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, 2018 at 12:28
  • \$\begingroup\$ Voting to close: please provide more information about the application. What are the transmitter (known: LVDS) and receiver (unknown)? Bandwidth? Distance, line losses, BER, or other signal level or SNR related concerns? If the question is a matter of resolving a confusion, please provide examples, background information, references, etc. illustrating your concerns. \$\endgroup\$ Jun 27, 2023 at 1:50

1 Answer 1

1
\$\begingroup\$

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.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.