<div dir="ltr">I was focused on " how narrow is possible" but that's a very good point.<br><br>Pete</div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sat, Sep 19, 2020 at 1:25 PM Oren Leavitt <<a href="mailto:obl64@ix.netcom.com">obl64@ix.netcom.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div>
<p>Looks nice!</p>
<p>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.</p>
<p>It's a VCOduino!</p>
<p>- Oren<br>
</p>
<div>On 9/19/20 12:40 PM, Pete Hartman
wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">
<div dir="ltr">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 ;).
<div><br>
</div>
<div>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.</div>
<div><br>
</div>
<div>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.<br>
<br>
<div><img src="cid:174a7bcb7cfbeec81521" alt="Screen Shot 2020-09-19 at Sep 19 12.05.02PM.png" width="236" height="562"> <img src="cid:174a7bcb7d01b171f502" alt="Screen Shot 2020-09-19 at Sep 19 12.06.12PM.png" width="249" height="562"></div>
<div><br>
</div>
<div>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.</div>
<div><br>
</div>
<div>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.<br>
<br>
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.<br>
<br>
It's half an inch between the rows of pins and .7" wide by
1.7" long total.</div>
<br>
Thoughts?<br>
<br>
Thanks!</div>
<div><br>
Pete</div>
</div>
</div>
<br>
<fieldset></fieldset>
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