How to derive the equations that rule the design of LC balun?

[Samy_75]

Hello,

I am newbie in the field of....... I want to learn how to derive the equations that rule the design of LC balun. I found this equation in several papers, but was not able to derive them from the circuit topology.
I hope someone could help to this.

Thanks,

Samy

 

[VSWR]

l-c balun

Sections 1 to 3 in this paper clearly describes how the equations are derived:

http://www.atmel.com/dyn/resources/prod_documents/doc8113.pdf

 

[biff44]

balun lc

I would not call that circuit a "balun"! I would call it "a crappy circuit the chip manufacturer needed to come up with because he made a chip with a differential output, but most customers want single ended output".

I am not surprised that the equations are bull.

 

[yendori]

lc balun circuits

You just calculate Xc, Xl to be 71 ohms @ Fc. The same way you calculate Xc,Xl to 71 ohms for a PI / TEE LC Balun.

 

[Mazz]

balun equations

Ehi biff, you're too strong with poor Atmel guys.

Indeed this is a classical and simple implementation of a balun, widely used to make his job, that is exactly: a circuit the chip manufacturer needed to come up with because he made a chip with a differential output, but most customers want single ended output.

Simple: one branch make 90deg the other -90deg with an impedance ratio.

Equations are correct.

Why you don't like it?

Mazz