3

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.

ocrdu
  • 8,705
  • 21
  • 30
  • 42
user1175197
  • 149
  • 3
  • Since your impedance ratio is 2:1 why do you even have to ask the question? –  Jan 07 '18 at 11:49
  • 2
    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. – user1175197 Jan 13 '18 at 07:38
  • 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. – KalleMP Dec 04 '18 at 12:28
  • 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. – Tim Williams Jun 27 '23 at 01:50

1 Answers1

0

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.