Square IC sockets?
sumdawgy
Posts: 167
I am looking at [URL=" http://www.ti.com/product/tca6418e/samplebuy"]TCA6418E- I2C Controlled 18 Channel GPIO Expander[/URL]
But It would be best if I could find the (or a) socket it seats in. anyone know where I should look? So far, I'm having no joy.
the pdf for the pin layout is here (also hyperlinked on the page).
But It would be best if I could find the (or a) socket it seats in. anyone know where I should look? So far, I'm having no joy.
the pdf for the pin layout is here (also hyperlinked on the page).
Comments
I'm sure others here can suggest more hobbyist friendly port expanders. Even just good old shift registers in DIP packages.
yea I still have 2-3 of those from an earlier project altho I wanna go i2c for the interrupt feature.
yea kinda why I'm hoping to find a socket out there. I was thinking of making one with a dremel and tiny springs.
Just thinking about it makes my eyse cross. (oh god, I've gone dyslexic)
As SRLM says you may find soldering it a bit hard and waste a bunch of chips and boards whilst trying.
Even if you succeed the end result is a break out board that will be as big as many of the other port expander DIP package solutions.
seems to have the adressing ability i was looking for and MIGHT make a replacement,
HOWEVER, more on topic I found this ..http://www.emulation.com/catalog/sockets/development/compression.cfm
which leads me to a more elegant solution....
setup pcb with pads in proper positions
I could protoype such a pcb then print it and etch it.
mount a "picture frame" to hold the chip in position followed by a top wich applies the compession to make a stable connection.
I agree with Heater on this. '595 for increasing outputs and '165 for increasing inputs. Communicating (and soldering/socketing) these chips is as easy as it gets.
I suggest you get a free sample. When you see how small it is you will soon give up the idea:)
You may even need a multi-layer PCB to allow routing of all the connections to those pins.
The 23017 gives 16 I/O and has interrupts, comes in SPI and I2C varieties, in a 28 pin dip package and is as cheap as err... chips
Dave
Agreed. If you made a board or found a break out board, you will need an oven to bake it. You can't solder BGA by hand.
Use the DIP versions or SOIC versions.
with a hotplate and USB microscope and flux pen. The microscope to check the alignment before heating,
for which fiducial marks on diagonal corners (in copper, not screen-printed!) are invaluable. Positional
accuracy is 100 microns or less perhaps, hence the microscope (a hand lens is subject to parallax error)
I'm tempted to say "that way madness lies". Still if you manage it then ordinary SMT is a doddle! I personally
find DFN/QFN quite stressful enough.
If you don't need the central 8 GPIO, you could perhaps treat it like a QFN, have elongated pads that extend well beyond the perimeter of the chip, and use hot air to see what happens.
It'd be a ~0.4mm pitch, good practice for Prop 2. You'd want to try and connect that inner ground pad though, if possible.
This company does the socket.
In fact, if they didn't have it, they'll make it for you.
BUT (here comes the devil's share, as usual), they are truly very expensive and you still has to deal with the problem of doing a breakout board to solder them.
There is another possibility:
This company has a solution very close to your needs, although at a .5 mm pitch (look at), BUT, they offer to help you finding whatever you need.
I believe that's possible that they even agree to make it, according to your own specs.
They also have an assembly service, to solder the parts on the boards, for you.
Sure they don't sell peanuts, but you can get what you want.
Hope it helps a bit.
Yanomani
The MCP23017 is very easy to use. It's a much bigger chip (physically), though.
yea that bothered me too.
well I'm thinking that i would need some 40 puts per floor alone....a lot of 8 bits would be needed.
I dunno I'm hoping to find a fairly reliable hack.
BUT if i must at least it's gonna be i2c (but with a lot of addresses.)
elegant, even if it does blow off some pins...
Well it's late just got off work gonna sleep on it.
the size kinda makes it easier to work with... and I DO like that it's 16bit
THANK YOU...I have some thoughts to try in the AM...... if they don't pan out...then I WILL go this way.:thumb:
Well I DID find a source. Test socket factory
Aries Electronics is a leading manufacturer of a broad range of interconnect products and Correct-A-Chip® technology.
reading thier site.....Aries Has Mastered These Manufacturing Processes... (blah blah blah...WAIT..) "Assembly of Solder Balls on Ceramic PC Boards & Connectors"
They also have quite a few more common ones on hand. Of course the rep for my location was on lunch during my call but I DID find that the thier 6.5mm max bga was configurable to my spec. The advantage here is mounting. Thier disclaimer is heat deforming the solder balls and causing failure. (fortunately for my purposes, there's no heat involved & next to no current.)
So untill I speak to ...(Well,I got his Email) my rep. . . I can't say if the price is in the hobby range. If they've not built one yet...gonna have to pay prototyping fees.
I am going to look around for a few other places but I imagine the prices will be similar unless I luckilly find one that already has some xbga-n25 sockets sitting on a shelf.
Give it up and go for one of the "normal" solutions suggested in the posts above.
Unless, that is, you are evaluating the chip to build the next gizzmo that you are going to sell in the hundreds of thousands or millions.
I suppose you have all the time in the world with your free chip samples but your $300 socket will still need mounting too. Do you know how illogical it is to pursue this course?
Test sockets are always $$$+ but as Heater mentioned that's not a problem when you are building squillions. What was that you say? At a hobby price. ROTFL
For sure a lot of other port expanders can be had for that price which are actually usable.
Well I wish someone had at least pointed me at test sockets in the first place ; ]
yea it may be a bit dreamy but until reality slaps you down... it might still be feasible.
But I agree a $300 price would be right out of hobby price.
But it's still a great dream.. the size makes a 60 output board smaller.
I think if anyone suggested "test sockets" they might have been slapped down, that's the reality. The only reason for these BGA packages is for automated volume production as they also require fine pitch multi-layer boards otherwise how do you route them? I avoid them as I like to stick to double-sided PCBs in small volumes (100s, 1000s).
But how would a big bulky socket make the board smaller??? Even the DIP version of the chip would be a lot smaller than the socket. All those pogo pins and ZIF mechanism etc takes a lot of space, these things were never designed to be dedicated to just one per chip. They aren't even really suitable for burn-in evaluation of a chip as you don't have the circuit characteristics that you would if it were mounted in tight on the board as it is designed to.
These sockets are fine for "testing" which really means either pre-programming or configuration, but the handling of each chip introduces both much more expense and also can increase the failure rate. I can buy a MEMS oscillator chip for under a buck but if it's handled by the distributor to program it my special requirements it costs three bucks. BTW, they are only tiny little 4 pin DFNs, not BGAs.
lol at the slap down
& yea I want to dream But even in that test socket ..if you note the picture....a few posts up....the test socket is still a bit smaller than a US quarter coin.
The prop's footprint is small ..but my accessory board(s) will dwarf it. (This is even before I add relays.)
I suppose I could mount it in an old ATX case.
If that is the same socket then it's still huge, 3D wise. Much bigger than any easy to solder DIP, QFP or even QFN etc.
Now if you want to dream in that fruitless and pointless manner, go to bed. If you want to dream up stuff that really makes a difference, then count the costs, weigh the pros and cons, and get into it, then tell us after, we may perhaps even applaud you. But never ever consider going to such great trouble and expense using your freebies just because they are freebies, as if that were some noble quest, it just makes you look very silly, and if you continue to be obsessed with "tilting at windmills" then don't be surprised when reality slaps you in the face and knocks you to the ground!
As a "Sancho", I will just look down and mutter something about " no one could have made any mistake about it but one who had something of the same kind in his head."