Can a transformer be used to convert single ended signal to differential signal?

Can a transformer be used to convert a single ended signal to differential signal?
If yes, then how? and why would one use a transformer instead of an opamp or some other method?

Yes.
Transformer...due to the symmetry of the windings, will guarantee a good 180 deg phase shift, and a good amplitude balance. And does not need a DC power source, and is immune to ESD damage. The drawbacks are the size, and sometimes the cost is higher. A benefit...if the differential output windings are center tapped, that is an excellent way to inject DC bias into the follow on circuitry.

How would you use an op amp? One inverting, and one non inverting stage? They are different topologies, so phase and amplitude tracking are questionable, also as the frequency increases, they might deviate even more since the basic op amp has limited bandwidth. Also the active device can have compression point issues generating harmonics or distorting your waveform.

Hi,

I don′t understand what this all has to do with "single ended to differential" conversion.

The benefits are: No DC power supply necessary, true isolation. A center tapped transformer has it′s benefits, but for simple solutions a single output winding should work, too.

Klaus

It is called a balun.

Converting Single ended to differential, a 1:1 transformer can be used, put say 100k to ground for each output wire, this forms the centre of the differential signal and ties it to the Ov of the following ckt, much lower resistors are used in some cases - depends on the input Z of the following ckt.

The centre tap of a 1: 1+1 xfmr does the same thing with very low Z.

Differential, generally means when one side is going up w.r.t. Ov, the other side is going down, (i.e. a mirror image about Ov, or 180 degrees out of phase for continuous repetitive signals).

Yes, high impedance audio transformer is the best choice

Transformer is the best method because of below advantages
1. Transformers output is isolated
2. It will effectively eliminate both the hum and buzz components
3. It having high CMRR performance

I do not understand your statement?
single ended to differential conversion is very often done with a transformer.

Hi,

True, I also recommended to use a transformer...
... but I don't see where or why one needs this features to get a "single ended to symmetrical" conversion:
* symmetry of the windings
* 180 deg phase shift
* good amplitude balance

Klaus

Klaus, we're in the RF subforum and discussing an RF/microwave balun.
The mentioned values are key specs for these devices.

Using a 1:1 Transformer to obtain Single-Ended to Differential conversion is not often good idea because of Bandwidth constraint.Bandwidth is defined by primary and secondary inductor values and stray capacitances of the transformer.I know there are wideband transformers but I prefer Transmission Line Transformer type Balun for the sake of simplicty.

as always, transformer size and bandwidth are relative to the required application, for DC to 200kHz, an array of 3 op-amps would be the preferred solution.

Tx's ( baluns in RF parlance ) are especially good where the input CM range is very great - including transients from lightning, mains spikes etc...