Custom calypso board

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Sébastien Lorquet sebastien at
Thu Jul 12 01:29:14 UTC 2012

Le 12/07/2012 01:06, Joachim Steiger a écrit :
> Harald Welte wrote:
> [...]
>> However, now that I think of it, PCIe requires PCB thickness to be
>> different (1.5mm) from what we are hading for (more like .8 or 1mm).
>> So I guess I'll scrap that idea.
> what about making it 2 pcb?
> one 'gsm module' with 'plated half holes'* and or board to board conn.
> one 'carrier board' which then has the right thickness for the pcie-con.
> that way the sandwhich is mechanical stable and the rf performance
> shouldnt be tampered with and can even serve as additional shielding if
> needed (e.g. make side opposite to the modem gnd flat).
> this makes the modules as small as possible for integration into
> different kinds of carriers or even a full phone.
> what do you think?
> [*]
> --
> roh

I was about to suggest the same thing.
A very small 6-layer board with minimal/critical functionnality (not 
even the sim) and then let people integrate that into simpler PCBs.
The RF can get out of the "critical" board via an UFL socket.

In the past, wavecom (now sierra wireless) had this idea. They developed 
a modem core on a small PCB, using bga on the backside instead of plated 
half holes. The packaging was made with a metallic shielding box.


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