Re: Guidelines to shrink the PCB size

On Nov 24, 11:35 pm, John Adair <g...@xxxxxxxxxxxxxxxx> wrote:
There many ways to shrink a design. As examples a switching power
supply where you can use a controller that switches at higher
frequencies to reduce magnetics size. Other aspects to consider are
the use of phyiscal package like QFN anf BGA which are smaller but
generally need a more expert setup for assembly. Our speciality of
FPGAs are often used to shrink several digital IC's into one device
saving space. When you shrink a design you will often need to use a
higher technology pcb e.g. more layers or a smaller track/gap
technology.

John Adair
Enterpoint Ltd.

On 21 Nov, 03:54, Ali <abdulra...@xxxxxxxxx> wrote:

Hello,

Are there any basic guidelines in embedded system when it comes to
shrinking the size? what are the probelms/limitations or interferences
one should consider while shrinking/sandwiching the board.

I was thinking that should be something like this:

0- Calculate the empty space in given housing. Thats the space actual
available for putting all the electronics.

1- Draft the physical dimensions of all components.

2- Now do simple PCB with few layers.
2.0- Break the PCBs in parts to fill the empty space,
connections can be done with ordinary connectors. Why not modularizing
the whole thing; LAN, Image sensor and Power circuitry etc. etc.
2.1- If the size is greater than free space then increase the
layers to adjust the components. (sure, we got to keep in mind the
heat emission and EMI if analog is involved)

3- Try to find components with different sizes with same specs.

4- And here we are in vicious cycle to fit all the thing in such a
small place , so lets start from point '2' again and keep iterating
unless we find the way-out of this puzzle.

Cheers,
ali

Guys, thanks for your kind suggestions, let me summarize the points
from 'jg' , 'Karthik Balaguru' , 'Paul E. Bennett' and 'John Adair '.

0- Start with Housing. Select a few candidate cases, and rank in
order of size if price is not an issue, and if it is then rank'em with
respect to size and price.

1- Draft the physical dimensions of all components.

2- Do CAD while focusing following things:

* Track separations to cope with high transient voltages.
* Track widths to carry the currents you expect
* Placing of circuit sections to maintain safety isolation
* The need for protection circuitry
* Room around the circuit to allow cooling airflow

2- Now do simple PCB with few layers.
2.0- Break the PCBs in parts to fill the empty space,
connections can be done with ordinary connectors. Try to modularize
the whole thing; Audio, RF, LAN, Image sensor and Power circuitry
etc. But be careful with insulation separation between boards (use
intermediate blank boards if necessary) and choose good quality inter-
board connectors.

2.1- If the size is greater than free space then increase the
layers to adjust the components. (sure, we got to keep in mind the
heat emission and EMI if analog is involved)

3- Try to find components with different sizes with same specs. Or
try to search a chips that incorporate many functionality to satisfy
your requirement.t

4- Try SMD packages and even consider things like circuit modules
which incorporate part of the design on a thin-film device (these can
some times use the chip die directly and place micro-sized additional
components around to make up more of the whole system).

5- Maybe you need to check ASIC, ASSP or FPGA if your design
incorporates standard mcu or dsp chores . And do give a try to
different packages too (QFN, BGA etc.).

6- Still in vicious cycle to fit all the thing in such a small place ,
so lets start from point '1' again and keep iterating unless we find
the way-out of this puzzle.


//ali
.

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