[sdiy] SSI2130

Oren Leavitt obl64 at ix.netcom.com
Sat Sep 19 20:23:48 CEST 2020


Looks nice!

Why not just go with a 0.6 inch wide DIP format? It'll fit a standard 
0.6 wide DIP socket and you'll have a little more wiggle room.

It's a VCOduino!

- Oren

On 9/19/20 12:40 PM, Pete Hartman wrote:
> I was inspired last night to take a crack at the idea of a breakout 
> that could have the chip pre-soldered.  I don't normally do a lot of 
> work with finer pitch SMD so I found I had to use fairly fine traces 
> to route to the pins with the chip rotated (which seemed to make the 
> most sense, since going to a DIP form factor).  Necking in KiCad is 
> not something I've mastered and I didn't spend a lot of time when I 
> found it wasn't working the way I thought the descriptions online said 
> it should.  PS: not looking for a debate about CAD packages ;).
>
> I'm curious if any of the more experienced would have any opinions 
> they'd care to offer?  Full disclosure: the intent is for this to be 
> sold as a DIY tool, so if providing advice for what might become a low 
> volume commercial product is a concern, by all means, don't feel like 
> you are obligated to comment.
>
> First the images.  I'm also sending pictures to the list for the first 
> time, so if for some reason this doesn't work, I can always throw 
> links to my google drive up pretty quickly.
>
> Screen Shot 2020-09-19 at Sep 19 12.05.02PM.png Screen Shot 2020-09-19 
> at Sep 19 12.06.12PM.png
>
> I liked the idea of having the regulator(s) on board, so I dug around 
> to find a couple that seemed likely.  I did find that -V regulators 
> were significantly more expensive (Q100 of both of these are under 
> $0.30,  Q10, and I didn't look for Q100, of even a pretty basic - 
> regulator was on the order of $3.00).  Since the chips tolerates up to 
> -18V I decided to forego a regulator on the negative rail.
>
> The V+ equivalent pin feeds the TLV1117-50, and that 5V feeds the 
> MCP1700-25 as well as the actual V+ pin on the chip.  I figured 
> someone might want to use their own different 2.5V reference so I put 
> a normally closed set of jumper pads that could be cut if preferred 
> (like the USB power on a teensy, for example).  This also allows you 
> to take the 2.5V reference *off* the pin if you wanted to use it for 
> expo scaling, or through zero, etc.  Sitting here this morning I am 
> thinking it might be a good idea to provide an extra pin at the top 
> edge so the 5V reference could be treated similarly.  I don't think I 
> could do exactly the same thing because there has to be some way for 
> the higher voltage to get onto the breakout.
>
> All the caps are 0603, which is about as small as I'd want to hand 
> solder; although I do not intend to hand solder it myself, I figured 
> leaving the option open even if just for prototyping seemed like a 
> good idea.  Same idea behind using "handsolder" footprints for the 
> regulator & reference.
>
> It's half an inch between the rows of pins and .7" wide by 1.7" long 
> total.
>
> Thoughts?
>
> Thanks!
>
> Pete
>
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