Limpkin's blog - My Business Card v2 - Comments<div>An electronics geek blog, dedicated to sharing and open source. Check out my stores: <a href="https://lectronz.com/stores/stephanelec" hreflang="en" title="Lectronz store">EU</a> / <a href="https://www.tindie.com/stores/stephanelec" hreflang="en" title="tindie store">EU & US</a>.</div>2024-03-29T00:41:47+00:00Mathieuurn:md5:51de6a3d917257edeff5a252fe925b02DotclearMy Business Card v2 - limpkinurn:md5:80272cbb6147fb781e189acaa93d21cb2014-10-03T23:41:09+02:002014-10-03T22:49:45+02:00limpkin<p>@<a href="https://www.limpkin.fr/index.php?post/2014/06/16/My-business-card-v2#c2498" rel="ugc nofollow">njneer</a> : Thanks! Please do... it's open source ;-) . Oh right, I forgot to explicitly mention that the ESD protection chip was changed indeed. Your ferrite is indeed alright. The crystal was changed to a 3.2x2.5mm (from a 5x3.2mm IIRC). </p>
<p>The milling was 1mm deep so the flash & leds could be hidden. I can send you solidworks files by email if you want!</p>My Business Card v2 - njneerurn:md5:c4427436a0308cefab40d3a8ac9f26222014-10-03T23:37:05+02:002014-10-03T22:40:54+02:00njneer<p>Really cool build! I hope you don't mind, but I'm trying to use your KiCad source to build one for myself, and hit a few snags that I figured I'd make you aware of. For one, it looks like there were a few changes to the BoM:<br />
USBULC6-2M6, a 6QFPN should now be IP4234CZ6,125, a 6TSOP (that has a different pinout than the USBULC5) <a href="http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail&itemSeq=158526443&uq=635479496151270323" title="http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail&itemSeq=158526443&uq=635479496151270323" rel="ugc nofollow">http://www.digikey.com/scripts/DkSe...</a></p>
<p>FB1 wasn't in the original board's BoM. I don't know a whole lot about USB circuits, but I'm guessing <a href="http://www.digikey.com/product-detail/en/BLM18PG121SN1D/490-1037-1-ND/584485" title="http://www.digikey.com/product-detail/en/BLM18PG121SN1D/490-1037-1-ND/584485" rel="ugc nofollow">http://www.digikey.com/product-deta...</a> would be a good choice (120 Ohm @100 MHz, 2A limit)</p>
<p>It looks like you're using a different crystal on this than the last one, as the crytal from the previous BoM is so large that it touches the pads for the decoupling caps on the new board when centered. Unfortunately, TXC doesn't make a smaller version of that oscillator, so I'm not sure what you used as a replacement.</p>
<p>For two, I feel like I'm missing something with the KiCad layout for the top board. It seems like there should be some kind of milling where the non-exposed components are. For example, over the flash chip, I realize that you didn't want it exposed, but if there's no milling there at all, the edge of the bottom board can't get flush with the edges of the top board. Similarly, for the LEDs on the ring on the bottom board, it seems like there needs to be half milling on the corresponding location on the top board in order to allow the boards to be flush. I'm used to working in Eagle as opposed to KiCad though... is there a way to specify partial milling (half the thickness of the board) in KiCad? Or did you just place the solder paste on the outer ring thick enough to make up for the height of the flash IC and the 0603 LEDs?</p>
<p>Thanks again for putting this all together!</p>My Business Card v2 - limpkinurn:md5:8a0e75f5807ea9faaf6e83e8320c7b4e2014-07-18T12:10:48+02:002014-07-18T11:11:47+02:00limpkin<p>@<a href="https://www.limpkin.fr/index.php?post/2014/06/16/My-business-card-v2#c2377" rel="ugc nofollow">euphonistihack</a> : (sorry for the late answer) the top board is indeed 1.6mm and the bottom 0.8</p>My Business Card v2 - euphonistihackurn:md5:54741ac4565451fd14bba9a974cea86c2014-06-25T16:23:42+02:002014-07-18T11:11:47+02:00euphonistihack<p>Another quick question: When you say that the total stack size is "2.4mm high (1.6+0.8)", does that mean you used a PCB thickness of 0.8 for the bottom board and 1.6 for the top? I would think the thicker 1.6 would be the top board to give as much clearance as possible for the components mounted on the bottom board, but wasn't certain.</p>
<p>Thanks again!</p>My Business Card v2 - limpkinurn:md5:a871f5b9de96d1521f87e0cf90d88bc82014-06-19T15:39:37+02:002014-06-19T14:39:57+02:00limpkin<p>@<a href="https://www.limpkin.fr/index.php?post/2014/06/16/My-business-card-v2#c2359" rel="ugc nofollow">euphonistihack</a> : thanks... yep!</p>My Business Card v2 - euphonistihackurn:md5:3ecdaf529f00246220fb6afbe867be442014-06-19T15:36:04+02:002014-06-19T14:39:57+02:00euphonistihack<p>Very cool build! Thanks for providing such a detailed writeup and sharing your kicad and software source. Is the only difference between v1's BoM and v2's BoM the change in microcontroller?</p>My Business Card v2 - limpkinurn:md5:9b0fcd387703ffbe5fdca0932c9e196a2014-06-18T17:09:18+02:002014-06-18T16:11:41+02:00limpkin<p>@<a href="https://www.limpkin.fr/index.php?post/2014/06/16/My-business-card-v2#c2353" rel="ugc nofollow">Fred</a> : Thanks!</p>
<p>Why did you cover one IC (the M25PX16 I think) but not the others? </p>
<p>>> Just for fun... and see if the interviewer wonder where the flash is.</p>
<p>Do you use standard LEDs that are just mounted upside down or are they LEDs that are specifically marketed as "reverse mount" LEDs. </p>
<p>>> Just standard 0603 LEDs on the bottom PCB. </p>My Business Card v2 - Fredurn:md5:c49b92cbc16570e3a32e6b1cf15502b32014-06-18T17:04:07+02:002014-06-18T16:11:41+02:00Fred<p>Definitely a nice improvement over v1. The diffused LEDs looks really nice. I have a couple of questions for you.</p>
<p>Why did you cover one IC (the M25PX16 I think) but not the others? Also, whilst the visible but protected components are a great idea, there's something odd about how they sit at the bottom of the cutout. I can't place my finger on how it could be improved but it just seems strange.</p>
<p>Do you use standard LEDs that are just mounted upside down or are they LEDs that are specifically marketed as "reverse mount" LEDs. These seem to be designed to sit on top of the PCB but shine light down through it. However, the more I look into these, the more confused I get!</p>My Business Card v2 - limpkinurn:md5:e1e91b3a2fed884ea207493b757508232014-06-18T09:53:21+02:002014-06-18T08:54:28+02:00limpkin<p>@<a href="https://www.limpkin.fr/index.php?post/2014/06/16/My-business-card-v2#c2351" rel="ugc nofollow">Zuinc</a> : Thanks! These are decoupling capacitors... rule of thumb is to put 100nF.</p>My Business Card v2 - Zuincurn:md5:3c3f5b863cbb0fc1f8e1360b3ddaea0b2014-06-18T09:47:21+02:002014-06-18T08:54:28+02:00Zuinc<p>Hi, Mathieu!<br />
Surprising news about the change of the job. I hope you found a better place to work. Successes and good luck to you!<br />
Question: how do You usualy calculate the value of C3, C4, C5, C6, C8, C10.<br />
Thank You!</p>