Interfacing PA with nRF51822

[Sreekanth]

Hello,

I would like to know whether the below PA can be interfaced with nRF51822? For our application we need to increase the power of the BT. so I have selected the below PA from skyworks,

1. SE2431L- can this be used to increase the range.
2. SKY66108- can this be directly connected to nRF51822 as this has a balun inside the FEM.

Thanks, Sreekanth

[Håkon Alseth]

Hi,

I would strongly recommend using our reference design for the BALUN of the nRF51x22. This will ensure that spurious and harmonics are filtered properly, especially since you want to add an external RF PA. This is something we cannot guarantee with generic RF PAs with integrated BALUN.

Based on this, I would recommend using a RF PA with single-ended 50 ohm input.

Cheers, Håkon

[Sreekanth]

Hello Hakon,

Thanks for the response.

We have proceeded with external BALUN as per the reference design (nRF51822) and single ended PA with 50 Ohm input.

Thanks, Sreekanth

[Sreekanth]

Hello Hakon,

We have the prototype board with us with PA (SE2431L) and nRF51822. The issue we are facing is that the range with the PA is very less. We are getting around 12mts inside the building. The Tx power we have set is 0dbm. As per the datasheet of the PA the output power Antenna will be +21dbm (VCC = +3.0 V, PIN = 0 dBm). In our design we are using BALUN in between PA and NRF51.

Do we have to tune the antenna? Any reference design will be helpful.

BR, Sreekanth

[Håkon Alseth]

Hi Sreekanth, Could you create a support case in MyPage: www.nordicsemi.com/.../mypage

And attach the schematic + layout (in gerbers) so that we can have a look?

Cheers, Håkon