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Topic: SMDs and 4-layer PCBs (Read 2 times) previous topic - next topic

Graynomad

Yes good point, PTH power devices often take up less space because they can be vertical and don't need a large heatsink plane around them as well. Bottom line is that power devices pretty much have to be a certain size for a given power and technology, you choose if that size is horizontal or vertical and in many applications vertical is using enclosure space that otherwise is not used and in fact you may even get a "free" heatsink in the metal enclosure.

In this case even a large PTH power transistor takes up almost no PCB space whereas it's SMD equivalent uses half the board.

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Rob
Rob Gray aka the GRAYnomad www.robgray.com

winner10920

One thing I like about smd is how nice it looks when everything is smd, very sleek and professional
im actually thinking about getting a sleeve tatoo one day with a self designed functional board
, thinking about having part of it so functional that I could trace it with that silver ink trace pen and put a tqfp 328p with some smd leds, maybe a small lipo battery taped to the underside of my arm for power and have the coolest single layer board out there

Grumpy_Mike

Quote
12 layer board...1000+ pin BGA chip...400mm by 300mm
Unbelievable,


This is a publicity shot of me "examining" the board.
http://www.flickr.com/photos/33177304@N03/6305319953/
You can see there are sockets for 10 extra boards to be plugged in. In all there were just over 8000 components in the system. .There are five large FPGAs on the board

winner10920

Wow, what could that be used for? I imagine a single board must cost thousands

Grumpy_Mike

Well close, the full unit was about $28,000 (boxed) and it was a very configurable transmodulator, taking satellite digital signals in at one end. Stripping the multiplex down into its component parts, assembling a new multiplex from those parts and re-modulating it as a digital cable signal. A sort of mini head end. It also allowed high speed data connections between the cable end and the box thus acting as an internet gate way, and multi-channel satellite system over poor quality coax lines that were already installed in buildings as communal antenna systems.   

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