Sample BCM20732S PCB Layout

Anonymous · ‎Apr 23, 2014

Hello Community Members,

This BLOG should be used as a "guide" for creating the PCB Layout for the BCM20732S Module.

The first attachments are:

BCM20732S_GERBER.zip - The gerbers of a sample layout.
BCM20732S_Allegro_CircuitBoard_Files.brd - Allegro circuit board file
BCM20732S_AltiumFootprint.PcbLib - Altium Foot Print
Sample_BCM20732S_Schematic.pdf - Schematic file.
BCM20732_SB-BLE-S03_PEVB_BRCM_V10_20130813_Allegro.dsn - Allegro Design File

Notes:

You can view this PCB file by downloading a FREE Allegro PCB viewer from the following link:
http://www.cadence.com/products/pcb/Pages/downloads.aspx

You will probably have to register on Allegro website before you can download the viewer.
Ensure you download this version: "Reads designs for versions 15.x to 16.6. Requires a Windows OS"

I will include a description after this post to discuss the details and answer any questions.

Thanks

JT

Anonymous · ‎Apr 23, 2014

Hey JT,

The BRD file you have attached is not an Eagle Board file it is an Allegro PCB file. You can view this PCB file by downloading a FREE Allegro PCB viewer from the following link...

You will probably have to register on Allegro website before you can download the viewer. Ensure you download this version: "Reads designs for versions 15.x to 16.6. Requires a Windows OS"

http://www.cadence.com/products/pcb/Pages/downloads.aspx

Regards,

Frank

Anonymous · ‎Apr 23, 2014

For anyone that is interested in Altium footprint I can send you an Altium footprint...just PM me

Regards,

Frank

Anonymous · ‎Apr 23, 2014

Thank you Frank. I have made that correction.

JT

Anonymous · ‎Apr 23, 2014

Thanks Frank - I have added that attachment as well.

Anonymous · ‎Apr 25, 2014

Hi Frank,

Can you please send me Altium version as well?

Anonymous · ‎Apr 25, 2014

Hi Alexander,

The Altium footprint was added to this post on Wed it is at the top of this discussion. Keep in mind the keepout area is somewhat flexible depending on your range requirements. If you want maximum range, ~150ft free air, you should ensure you are adhering to the recommend keepout area specified in the Datasheet.

Regards,

Frank

ShawnA_01 · ‎Apr 29, 2014

Hello J.T.

The 4/18/2014 20736S Technical Reference Manual states pin 38 is a ground pin.

However, the BCM20732S_Allegro_CircuitBoard_Files.brd provided shows Pin 38 as not connected.

20736S uses same pinout as 20732S.

Other schematics I've viewed show pin 38 connected to ground as well.

What's up?

Thank you!

4-29-2014 9-39-02 AM.png

Anonymous · ‎May 01, 2014

Is there any smaller PCB layout example?

I'd like to make a board with 20x10mm size.

I don't need ~150ft range. So please give your advice.

MichaelF_56 · ‎May 02, 2014

The thread created here discusses some of the tradeoffs associated with changing the recommended PCB layout: Re: BCM20732 layout options

Essentially, if you are ok with scarificing the 31–41% antenna efficiency specified using the recommended layout (~50m range), several parameters with the PCB design can be changed.

Anonymous · ‎May 02, 2014

Please tell me reduced size of each parameter for 20x10mm pcb.

Should I discuss with another thread you introduced?

Anonymous · ‎May 22, 2014

Hello JT,

Page 23 refers to Fig 9 and in particular to the clearance area (marked in yellow). What are the dimensions of this area? It looks larger than the specific dimension given for the keep-out area defined a few pages earlier. Is it just a case of the more the better?
Page 26 at the bottom, there is a note advising not to route the GND plane under the RF pin. Which pin in the RF pin? (I beleive it is pin 10 but the latest TRM simply lists pin 10 as "reserved").
Page 27 The dimension on Fig 14 is obviously incorrect.

Thanks,

JP

ShawnA_01 · ‎May 28, 2014

The packaging house (SPIL) has confirmed Pin 38 does not attach to the die.

Anonymous · ‎Nov 18, 2014

What is the recommended PCB thickness for this device?

MichaelF_56 · ‎Nov 21, 2014

I checked with J.T and our internal PCB guru and they confirmed that the TAG development board PCB is 1mm thick.

Anonymous · ‎Feb 10, 2015

Placing the BCM20732S on the bottom of the PCB, could this choice create an issue for the device receiveing two thermal stresses for a double side PCB circuit?!?