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Sample BCM20732S PCB Layout

Anonymous
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Sample BCM20732S PCB Layout

Hello Community Members,

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

The first attachments are:

  1. BCM20732S_GERBER.zip - The gerbers of a sample layout.
  2. BCM20732S_Allegro_CircuitBoard_Files.brd - Allegro circuit board file
  3. BCM20732S_AltiumFootprint.PcbLib - Altium Foot Print
  4. Sample_BCM20732S_Schematic.pdf - Schematic file.
  5. 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

Attachments
Comments
Anonymous
Not applicable

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
Not applicable

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

Regards,

Frank

Anonymous
Not applicable

Thank you Frank.  I have made that correction.

JT

Anonymous
Not applicable

Thanks Frank - I have added that attachment as well.

Anonymous
Not applicable

Hi Frank,

Can you please send me Altium version as well?

Anonymous
Not applicable

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
Employee
250 replies posted 100 likes received 100 replies posted
Employee

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
Not applicable

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
Moderator
Moderator 250 sign-ins 25 comments on blog 10 comments on blog
Moderator

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
Not applicable

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

Should I discuss with another thread you introduced?

Anonymous
Not applicable

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
Employee
250 replies posted 100 likes received 100 replies posted
Employee

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

Anonymous
Not applicable

What is the recommended PCB thickness for this device?

MichaelF_56
Moderator
Moderator 250 sign-ins 25 comments on blog 10 comments on blog
Moderator

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

Anonymous
Not applicable

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?!?

Anonymous
Not applicable

Hello Luigi,

I think you are correct, but we have no empirical data.

Thanks

JT

ThYo_2228536
Level 3
First like received First like given
Level 3

Hi for the PCB layout looking at the BCM20737L Datasheet I was wondering what is the part in dark green ?

pastedImage_0.png

ThYo_2228536
Level 3
First like received First like given
Level 3

Anyone ?

BoonT_56
Employee
500 likes received 250 likes received 100 likes received
Employee

thomasyounsi

It is actually the L-shape ground requirement for the embedded antenna. Below is a better picture:

20732S.jpg

I would like to refer you to the below doc which will explain in greater details (pg 21 to 25):

BCM20732S Bluetooth Low Energy SiP Module Technical Reference

Version history
Revision #:
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Last update:
‎Apr 23, 2014 12:19 PM
Updated by:
Anonymous
 
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