Impedance 2.4 GHz balun

Balun: Balanced to Unbalanced transformation ! The fact that these devices can be used to provide impedance transformation as well is a bonus!

I don't see anything about a centre-tap on this page

The balun you mention is a 1:1 ratio. They also have 1:2 and 1:4 devices for the same frequency.

René wrote: : I like to use a balun like the Murata LDB212G4005C-001 for a Zigbee : project.

I happened to use those same baluns together with a MAX2701 downmixer instead of the LDB15C500A2400's specified in the MAX2701 eval kit datasheet. I believe the device is a Guanella-style balun, and any of the GND's in the package drawing do not refer to a centre tap, but to the ground plane of the transmission lines (which is also the GND for the unbalanced port of course). They are 1:1, i.e. 50ohm-50ohm devices.

Regards, Mikko

That's another thing. If one sees how these parts are used in actual cicrcuits, 2 is the center tap (hf ground and port bias), while 5 is the unbalanced ground for pin 1.

Indeed this is not to be derived from the datasheet, but pins 2 and 5 are *not* interconnected, pin 2 has DC contact with 3 and 4 only.

If I read you right, pins 3-4 and 1-5 are 1:1? If so, what do you consider the impedance 2-3 and 2-4 individually (unbalanced side terminated with 50 ohms)- 25 Ohms...or 12.5 Ohms? :-)

For the other poster: I would use the balun for both balance / unbalance conversion as well as impedance transformation. It seems that my theoretical calculations clash with actual application as I find it in working evaluation samples. No doubt I got it wrong, but I like to understand it....

Thanks for reacting!