CC1310 - Combining TI ref. design with chip antenna matching circuits

Henrik Sandaker Palm

Intellectual 975 points

Take for instance TI ref.design (2 layer 0.8mm):

SimpleLink CC1310 2-Layer 7x7 Differential 779-930 MHz v1.3.3 Design Files

Has this balunfilter matching circuit:

And take for instance JTI part 868 and 915 MHz wideband chip antenna:

Compared to other manufacturers of similar chip antennas, the matching circuits looks much the same.

Question is: should the balunfilter matching circuit from TI ref. design and this chip antenna matching circuit coexist on the PCB, or are parts of them substituded with each other?

over 8 years ago

0 TER over 8 years ago

TI__Guru**** 317180 points

Every thing left of C15 (and including C15) should not be changed. Add the required matching after C15.

0 Henrik Sandaker Palm over 8 years ago in reply to TER

Intellectual 975 points

Thank you!

0 jaydeep Panchal over 8 years ago in reply to TER

Intellectual 415 points

Dear Ter,

From Where should I start 50Ohm Impedance Track? After c15?

Thank You,

Jaydeep

0 TER over 8 years ago in reply to jaydeep Panchal

TI__Guru**** 317180 points

Yes

0 jaydeep Panchal over 8 years ago in reply to TER

Intellectual 415 points

Dear TER,

would you please review attached Layout. Board size is 32x30mm

Thank you,

Jaydeep Panchal

0 TER over 8 years ago in reply to jaydeep Panchal

TI__Guru**** 317180 points

- Vias: It looks like one of the only places where you have placed vias to ground is around the RF track. Note that all pads connected to ground should have a via next to it.
- DCDC: Is the layout of the DCDC according to the reference design?
- The LNA network should be symmetrical
- After the balun you have a pi network (before the cap that goes to the antenna tuning). One of the caps in this filter should be rotated 180 degrees.

0 jaydeep Panchal over 8 years ago in reply to TER

Intellectual 415 points

Thank you Dear,

-i am trying to place via next to the pads connected to GND. SOme of the pads(connected to gnd) may not have via next , is it ook?
-i am checking dcdc layout in reference design and i will follow it.
-LNA network is symmetrical (except at starting point of RF_P Pin). can i ignore it?
-i am inverting one of the cap.

:-)

0 Krishna Kumar4 over 8 years ago in reply to TER

Expert 1565 points

Just for the newly initiated, can you please point out what is the significance of vias next to all pads that are connected to ground? Is this still needed if the copper pour on the layer itself is Ground?

0 TER over 8 years ago in reply to Krishna Kumar4

TI__Guru**** 317180 points

The most important is that the decoupling caps has a short as possible ground route back to the die paddle (chip ground). To achieve this a via close to the pad is fairly often required.

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CC1310 - Combining TI ref. design with chip antenna matching circuits