CC2520-CC2591EM Reference Design (6-Layers Stack-up)

Irfan Maqsood

Other Parts Discussed in Thread: CC2591, CC2592

We are using CC2520-CC2591EM Reference Design for CC1101QRHBRG4Q1 + CC2591RGVR. Reference PCB layout has 4-layers stack-up however due to our design requirements we have to use a 6-layers stack-up. However, in 2.4 GHz RF module we poured the extra two layers with GND planes. Board thickness is same i.e. 1.6 mm. Do you see any issue with this change of stack-up?

over 7 years ago

0 TER over 7 years ago

TI__Guru**** 317180 points

I assume it's a type here since you write that you use CC1101QRHBRG4Q1?

The most important parameter in the stack-up is the distance between the signal layer and the first ground layer, this should be the same as in the ref design.

0 Irfan Maqsood over 7 years ago in reply to TER

Prodigy 110 points

Yes, that was a typo. we are using CC2500RGP+CC2591RGVR

0 Irfan Maqsood over 7 years ago in reply to TER

Prodigy 110 points

In reference design, the distance between signal layer and first ground layer is 0.175 mm. However, in our design it is 0.15 mm. Is it acceptable or we should increase it to match with reference design?

0 TER over 7 years ago in reply to Irfan Maqsood

TI__Guru**** 317180 points

CC2591 is a sensitive device in the sense that the performance is very dependent on the layout. So for designs with this chip I would use the same distance as the ref design.

0 Irfan Maqsood over 7 years ago in reply to TER

Prodigy 110 points

We will update the stack-up to match the distance between outer signal layer and next ground plane with reference stack-up. However, in application notes (www.ti.com/.../swra229a.pdf), on page 10, it is strongly prohibited a deviation from reference design but as per your recommendation/experience we can achieve it as far as we are keeping the distance same?

0 TER over 7 years ago in reply to Irfan Maqsood

TI__Guru**** 317180 points

If you keep the distance between the signal layer and the first ground layer the same the parasitics will be the same. Due to the ground layer the layers under this will not have an impact, from a RF point of view they will not be visible. If the total board thickness is the same the vias will have the same inductance etc and from CC2591s view a 4 and 6 layer design will look the same.

Note that for new designs we recommend CC2592 since this frontend is easier to use than CC2591.

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CC2520-CC2591EM Reference Design (6-Layers Stack-up)