AFE7769: AFE7769: Layout suggestion || RF side

Hi,
Please Provide your comments for the Above mentioned query 

Hi Pavan,

I believe this requires some discussions:

Regarding

Pavan Kalyan said:

We are Planning to give isolation with shield on TOP and Bottom i.e (for TX & RX ) 

Please advise the channel-to-channel isolation requirement within the RX and within the TX. The best way to evaluate this is to check this on our AFE7769 EVM to ensure the channel-to-channel isolation within RX channels themselves or TX channels themselves are acceptable. We have the specifications in the datasheet.

The most concerning limitation on the isolation is actually the passives like baluns and inductors. Since baluns and inductors have magnetic properties, the leakage amongst these passive are significant. It is best to place them in perpendicular fashion in the layout. Please advise if VVDN have such experience with these passive layouts. The mechanical metal chamber designed should also account for the channel-to-channel passive isolations.

Pavan Kalyan said:

For the feasibility of routing we might need to use one Via on single ended Signal for TX and RX

I believe this is fine. I am picturing the following: you can keep the RX differential traces + differential matching components + balun on one layer, and then transition the single-ended via to the top or bottom layer that you would like.

What would help us to analyze is for VVDN to provide a preliminary block diagram of the RF line-up, and indicates which components are on the same layer as the AFE7769 (without need for via transitions), and which components are on the opposite layer (needing via transition), and note any via transitions. I am not asking for a layout yet as layout will consume quite amount of design time. I am just asking for a routing plan. I believe Deepak has the signal chain line-up block diagram. If you can just add comment on which components are on the same layer as the AFE7769D, and which components are on the opposite layer of the PCB, TI can then review and provide feedback.

Please also include which components are within the mechanical "shields" so we can get some idea on how the passive interference can be minimized.

Pavan Kalyan said:

And ORX signal we are Planning to route in the internal layers with GND Planes on the top and Bottom.

This is fine. Keep in mind the stack-up need to be setup as 100ohm differential as the ORX port has 100ohm termination. The same suggestion applies to ORX as earlier: please advise the routing plan for us to review.

TI will also discuss this internally and get back to you.

-Kang

Hi Kang,
Thanks for your response.
We have Shared more Details via Mail

Regards 
Pavan Kalyan

Pavan,

We have shared your email internally with team members for their review. We will follow up with you via email.

Thanks,

Serkan