CC8531: Impedance matching Johanson 2450AT18D0100E to CC2590 & CC8531

Soroaj G

Part Number: CC8531
Other Parts Discussed in Thread: CC2590

I am designing a microphone using CC8531 & CC2590. Since I am aiming for a small form factor, I have decided to use a chip antenna instead of the PCB antenna on the evaluation board designs. As far as I understood, I should maintain the matching circuit the same and replace the antenna with the recommended passives from the antenna manufacturer. I have chosen Johanson 2450AT18D0100E. I am posting my schematics here. It would be great to get a confirmation if my design is alright.

over 3 years ago

0 Soroaj G over 3 years ago

Prodigy 30 points

0 FI over 3 years ago in reply to Soroaj G

TI__Mastermind 20210 points

Hi,

The output of the CC2590 is not 50Ohm so I would not recommend using the stated balun after this device. It may cause instability.

Also see this e2e.ti.com/.../873769

Regards,

0 Soroaj G over 3 years ago in reply to FI

Prodigy 30 points

Hi, I think I may not have included all the required details. I wish to only replace the PCB antenna with a chip antenna. I am not using any new balun. I am using the matching network as the reference design. As shown below, the ANT signal is the output of cc2590 and the reference matching network is included along with an additional pi network for final fine tuning using a spectrum analyzer.