SugarAddict 227 Posted January 6, 2012 Share Posted January 6, 2012 Autorouted... But that's what I was thinking, sorta. Quote Link to post Share on other sites
RobG 1,892 Posted January 6, 2012 Author Share Posted January 6, 2012 Autorouted... But that's what I was thinking, sorta. Reminds me of Piccolo TI last year rolled out some really cool, extremely tiny DC/DC stepdowns. I think they might do the trick. TI also rolled out the simple switcher nano modules just a few months ago. The down side to the simple switcher is that it requires 5 basic components (3 Capacitors, 2 resistors) I am thinking of using TPS62056, TPS62172, or the popular MC33063A. I may have to make all parts 0603 to accommodate DC/DC. Quote Link to post Share on other sites
SugarAddict 227 Posted January 6, 2012 Share Posted January 6, 2012 Make it all 0402. If you think that's too small to solder, send it all to me and I'll solder it for you if I can keep 1 lol I was wondering... why not try for QFN? .794" x .894" and 4 Buttons! (because I was bored) Quote Link to post Share on other sites
RobG 1,892 Posted January 6, 2012 Author Share Posted January 6, 2012 To make the final version, I need your opinion on few things. 1. All parts will be 0603. SA suggested 0402, but I want this board to be sort of friendly with non-SMD folks since there will be options. 2. I will remove RST switch. If a manual reset is required without shutting down the power, pins 1 and 2 of J2 can be shorted. 3. Should I keep the crystal? I think yes. 4. Should I keep xtal capacitors or are the internal ones enough? 5. Regulator. I am thinking one is needed, but trying to determine which one. a) LDO - for things like 5V systems and 6V toys with enough juice to spare. Vin < 6V Small DC/DC - like above and things that are powered by 9V batteries. Vin < 10V c) Better DC/DC - like above plus 14V automotive applications. Vin < 16V 6. Should the regulator be a) <300mA, MCU 800mA-1A, MCU + LED displays for example. This will however require another pin on J1 or dedicated power header Quote Link to post Share on other sites
SugarAddict 227 Posted January 7, 2012 Share Posted January 7, 2012 Internal are fine as long as you aim for 12pf or lower which is a piece of cake. Can you make this one board and the regulator another since you are looking at 3 inputs? (A close stacking effect?) Then both would be useable together or separately... Both would be AWESOME by themselves if done right and you're doing it right Quote Link to post Share on other sites
RobG 1,892 Posted January 7, 2012 Author Share Posted January 7, 2012 I think I am done, for now at least ( I just have to adjust few tiny things.) Moved everything around, added 500mA TPS62172 (TPS62162 can also be used which is 1A.) @SA, can you make a sketch? Quote Link to post Share on other sites
SugarAddict 227 Posted January 7, 2012 Share Posted January 7, 2012 sketch? of what?... 2 boards? I was thinking separate the power so you had 3 inputs (only 1 used at a time... jumper selection?) on one board and it would have 2 2pin headers, 1vcc 1gnd on one end and 1 vcc 1 gnd on the other end, this would attach to your board which you could remove the power stuff from and just take straight vcc/gnd connection from the power board... get it? Quote Link to post Share on other sites
RobG 1,892 Posted January 7, 2012 Author Share Posted January 7, 2012 I think I do now, it would be a power daughter board. (this is just a quick mock up) Quote Link to post Share on other sites
SugarAddict 227 Posted January 7, 2012 Share Posted January 7, 2012 Move JP1 or JP2 to the other side... this way it actually sits on there a bit stable and doesn't sandwhich together on one side... and if people don't mind sandwhich, then they have a 2nd JP set to use for more boards Quote Link to post Share on other sites
RobG 1,892 Posted January 8, 2012 Author Share Posted January 8, 2012 OK, so here are two more iterations. First one has a 3 pin connector and two support holes/pins (for bigger daughter boards.) There is also a room for optional TPS77xxx LDO. Second one has 2 x 2 pin headers, as suggested by SA. There's also a mock up of a simple TPS based DC/DC. SugarAddict 1 Quote Link to post Share on other sites
RobG 1,892 Posted January 12, 2012 Author Share Posted January 12, 2012 OK, the design is finished, ready for Seeed. The nanoPad is on the bottom left. There are 3 LEDs with jumpers on the board, optional TPS77xxx LDO (up to 5.5V input, 250mA) and headers for the daughter board. P2.4 and P2.5 can be connected to the daughter board using jumpers. Little bit higher is the power board. It is TPS6205x based DC/DC step-down (up to 10V input, 800mA) fixed or adjustable, and low battery condition output. On the right side is the battery board, which should accommodate 12mm and 20mm battery holders. Daughter boards are 0.9" x 0.3" Updated 1/12 bluehash 1 Quote Link to post Share on other sites
nobody 47 Posted January 12, 2012 Share Posted January 12, 2012 Why did you completely ignore the design rules? TPS6205x based board needs to be revised. Path between TPS6205x and blocking capacitors must be the shortest as possible. C10 is necessary to move the left edge. C11 is a need to move under the coil (between coil and NanoBoard, not at the opposite layer). And between the boards is not gap to cutting. Quote Link to post Share on other sites
RobG 1,892 Posted January 12, 2012 Author Share Posted January 12, 2012 I wouldn't say I have ignored them (considering available space and package sizes,) they "should be" as close as possible. The only offender is C10 on the input side and yes, now it's obvious it can be moved (this is why I post this stuff, so people can help with improvements.) My initial goal was to make low profile board with all parts on the top layer, then I have decided to add parts for LBO and FB so bottom layer can now be used too. That said, I will take another stab at it so that everybody... or nobody is happy Posted updated image above. Quote Link to post Share on other sites
RobG 1,892 Posted March 1, 2012 Author Share Posted March 1, 2012 Finally, boards are here, assembly time (note to self: never order boards right before Chinese New Year.) And the power supply board SugarAddict, GeekDoc, greeeg and 3 others 6 Quote Link to post Share on other sites
zwitt 0 Posted March 3, 2012 Share Posted March 3, 2012 Hi, is there any possibility to buy this board , or to download a final version ? Thanks Zbig Quote Link to post Share on other sites
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