zeke 693 Posted November 21, 2011 Share Posted November 21, 2011 Page 6 of the datasheet says: Stability The ZLDO1117 requires an output capacitor as part of the device frequency compensation. As part of its improved performance over industry standard 1117 the ZLDO1117 is suitable for use with MLCC (Multi Layer Ceramic Chip) capacitors. A minimum of 4.7?F ceramic X7R, 4.7?F tantalum, or 47 ?F of aluminum electrolytic is required. The ESR of the output capacitor should be less than 0.5?. Surface mount tantalum capacitors, which have very low ESR, are available from several manufacturers. When using MLCC capacitors avoid the use of Y5V dielectrics. For the output cap, you have some latitude: You could pick: - a 1206 sized, X7R Ceramic cap - say 22uF/6.3V or, - a 1206 sized, X5R Ceramic cap - say 47uF/10V For the input cap, I would pick a 10uf ceramic with a voltage rating specific to your application. I think the reg can handle 18V maximum so you might want to accommodate that. BTW, the datasheet says that the reg needs a 100uF output only under certain conditions. If you really think that you need 100uF then put two 47uF in parallel at the output and you'll be good. Does that help? bluehash 1 Quote Link to post Share on other sites
bluehash 1,581 Posted November 21, 2011 Author Share Posted November 21, 2011 Sounds good. 47uf/10v will be the one. We need only 3.3V out Thanks for the links. Quote Link to post Share on other sites
GeekDoc 226 Posted November 21, 2011 Share Posted November 21, 2011 We need only 3.3V out Darn. I was hoping for 5v as well. Quote Link to post Share on other sites
bluehash 1,581 Posted November 21, 2011 Author Share Posted November 21, 2011 Let me see if I can accommodate. Maybe get a 5V ldo and divide it down to 3.3V or two LDOs. Quote Link to post Share on other sites
TopHatHacker 25 Posted November 21, 2011 Share Posted November 21, 2011 TLE4476_DS_25[1].pdf.pdf] what about something like this? datasheet seems like it doesn't need many components. Quote Link to post Share on other sites
bluehash 1,581 Posted November 21, 2011 Author Share Posted November 21, 2011 Good find...adds $4.0 to the cost. Not enough to run a motor though. Will people be really needing dual supplies on a BB? Quote Link to post Share on other sites
PentiumPC 119 Posted November 21, 2011 Share Posted November 21, 2011 2 x fixed voltage LDOs. Make board with traces for 5v and 3.3v but solder what you need?? Quote Link to post Share on other sites
bluehash 1,581 Posted November 21, 2011 Author Share Posted November 21, 2011 Hmm.. yes. Keep the pad and solder what you want. This will be great as a kit. Quote Link to post Share on other sites
DrMag 14 Posted November 21, 2011 Share Posted November 21, 2011 I've had a lot of success with Linear's LT1763. It'll get you 500 mA at $2.79. There are fixed values including 3.3V and 5V too. Edit: The LT1963A seems to be a beefier version (1.5 A) at $3.57 bluehash 1 Quote Link to post Share on other sites
RobG 1,892 Posted November 21, 2011 Share Posted November 21, 2011 Here are some regulators I got from Arrow: MC33269DT-3.3G LDO 0.8A $0.33 TLV1117-33CDCY LDO 0.8A $0.37 UA78M33CDCYG3 0.5A $0.29 bluehash 1 Quote Link to post Share on other sites
GeekDoc 226 Posted November 21, 2011 Share Posted November 21, 2011 Let me see if I can accommodate. Maybe get a 5V ldo and divide it down to 3.3V or two LDOs. Hey, I'm not the only one interested in this board. Others may want to keep it at 3.3V. I gotta quit posting these opinions... people keep taking me seriously. :? Not just here; I posted an opinion on an Android developer's site and he added two features based on my input alone! Public Service Announcement: I am a noob! I should usually be quietly ignored or patiently instructed. Quote Link to post Share on other sites
RobG 1,892 Posted November 22, 2011 Share Posted November 22, 2011 Some of the greatest ideas come from noobs because people with experience are usually opinionated Quote Link to post Share on other sites
GeekDoc 226 Posted November 22, 2011 Share Posted November 22, 2011 Swapped my sig for that PSA. Quote Link to post Share on other sites
MattTheGeek 99 Posted November 23, 2011 Share Posted November 23, 2011 What about using DC-DC Stepdown/Stepup Converters? Quote Link to post Share on other sites
PentiumPC 119 Posted November 23, 2011 Share Posted November 23, 2011 Let me see if I can accommodate. Maybe get a 5V ldo and divide it down to 3.3V or two LDOs. Hey, I'm not the only one interested in this board. Others may want to keep it at 3.3V. I gotta quit posting these opinions... people keep taking me seriously. :? Not just here; I posted an opinion on an Android developer's site and he added two features based on my input alone! Public Service Announcement: I am a noob! I should usually be quietly ignored or patiently instructed. Nah.. this just show you have good ideas. Quote Link to post Share on other sites
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