Best Way to inter-connect PCBs

[jkeny]

I just about finished the TAS1020 USB board - now looking for connectors. This is a bugger as I want to make the thing modular so I can plug in different DACs/IV stages/Other trick boards I'm building - I only need 4 pins for the I2S lines - I thought about using headers & sockets (I like the price & the idea of just cutting off what I need) but they seem a bit flimsy & can be plugged in incorrectly.

I want to keep the I2S length as short as possible (high speed signals) so don't really want to use cable. I could end up with a stack of 4 - this board + Signal bias board + DAC + IV stage. Maybe only the ones carrying the I2S need to be short (stacked), the IV can be cabled? - still leaves 3 boards stacked.

Any experience of stacking PCBs with connectors? Criteria are:
- flexibility & price - don't want 25 pin shielded expensive do-da when I only need 4 pins
- would be nice to have 90 degree connector option to plug in some boards end-to-end rather than stacked
- would be nice (nearly essential) to have some way of avoiding plugging in incorrectly.

[ratza]

I had a project at work some time ago and I had the same issue, just that there were 6 signals to connect. I did it very simple with 50 mills pin headers and sockets. At the begining of the pins I pulled one out from the insulator and I filled with glue the corresponding plug. In this way you cannot connect it in the wrong direction because of the filled hole. I can do a drawing, if needed.

P.S. ...and yes, I know that a moron can shift the connector and mess averything.

[Mr Evil]

I have used DB-9 connectors for this sort of thing before. They're not exactly ideal, but they are physically secure (can be bolted together if even more strength is needed) and cheap. 90 degree ones exist, and they can only be plugged in one way due to the shape.

[BrianDonegan]

Just use pins and headers and be careful connecting them (don't mis-align). It is cheap and will afford you the greatest flexibility.

I2S can stand to be longer. You will actually want to keep the path to I/V as short as possible, more so than the I2S.

[jkeny]

Wow - I missed this forum - 3 replies already! (Don't ya love the way it zooms pics for you)

Ratza, nice bit of lateral thinking - that makes the header + socket more interesting - it only has the issue of flimsiness now - maybe putting in an extra offset row just for support would work (and could guarantee immunity from morons - I number myself among these)?

Mr Evil, DB9 connectors are a bit difficult to insert & remove - in my experience. And this is an experimenters platform so lots of push-pull

Brian, OK so I need short signal path to IV stage also - this is why I post here - it stops me making stupid mistakes

Edit: What are these board stackers & how are they used - I can't work them out how they plug together http://www.globalconnectortechnology....aspx?pn=BG020

[ratza]

Originally Posted by jkeny

and could guarantee immunity from morons - I number myself among these?

Moron immunity cannot be guaranteed, they always seem to be smarter. I did not refer to you, although it might happen to connect it in the wrong way when you are tired and you don't pay enough attention. To be honest, that's why I did the connector in this way

Originally Posted by jkeny

Edit: What are these board stackers & how are they used - I can't work them out how they plug together http://www.globalconnectortechnology....aspx?pn=BG020

Those are normal pin headers but used to rise the board connected in the upper side.

[jkeny]

Ah, yes they're just longer pins with knobbly bits.

I know you weren't referring to me but I think we can all be morons when tired or drunk or just pre-occupied & losing a piece of kit like this is a PITA (I've done it, I know) - blew some nice BBC LS3/5A woofers when tired. Ohh the horror!!

Anyway, two rows of pins staggered seems like a good way to go!

Next question - Which makes a better contact, round or square pins - as I said I'm using it for high speed signals & low impedance will matter!

Where's the best/cheapest source ?

[ratza]

I really don't know which type has better contact. The resistance is around 20 milliohm anyway.