Hi Richard, Maybe use a LD1117, not too expensive 0.5..1 Euro, not too hard to find (local electronics shop) and available in TO220 housing (homebrew friendly_) http://nl.farnell.com/stmicroelectronics/ld1117v33/v-reg-ldo-3-3v-1117-to-220-3/dp/9755837 Albert
On 1 sep, 11:04, Richard <[email protected]> wrote: > Hoi Seb and Albert, > > In our situation I would like to use a LDO because the dropout voltage > of the LM317 can exceed the 1.7V (I >= 500mA Tamb < 25degree). > > What about the LM2937ET-3.3? or the LF33CV (seewww.rs-components.com > artnr: 355-4128) > > -Greetz > > Richard > > On 31 aug, 23:30, "a.faber" <[email protected]> wrote: > > > > > If the 3.3 volt regulator is hard to find, why not design it with the good > > old LM317 and two resistors? > > Albert > > > ----- Original Message ----- > > From: "funlw65" <[email protected]> > > To: "jallib" <[email protected]> > > Sent: Monday, August 31, 2009 11:13 PM > > Subject: [jallib] Re: Jaluino next version: what could be added/improved > > > Hi Sebastien, > > > I looked again on Arduino site at their hardware specifications > > starting from Nano, Diecimila to Duemilanove and Mega. All boards are > > using the 5V source for powering the microcontroller and the board. If > > an external source is lower than 7V can cause board instability. > > The 3.3V power is provided by FTDI and can draw a maximum of 50mA. Is > > provided for shield and is fragile in my opinion. > > Jaluino can have a more powerful regulator. Having a 3.3V source > > available for shield is a good option (very handy). > > > But, if others can't easily find a 3.3V voltage regulator, the board > > still can be built and used because 3.3V is only for shield use (if > > required - it can be soldered later). Anybody can find a 7805 5V > > regulator. > > > My opinion... > > > Regards, > > Vasi > > > On Aug 31, 10:13pm, Sebastien Lelong <[email protected]> > > wrote: > > > Hi Richard, > > > > I can't guess which is the most used, which make more sens: > > > > 1. 3.3V/5V selection for board and shield, or > > > 2. 5V on board and 3.3V shield with voltage adjustments... > > > > If we follow Arduino design, I think (but I'm not sure it is the same on > > > all > > > *duino flavors) it corresponds to just 3.3V on spare pin, that is option > > > 2. > > > > > > OK, I'll try to find one of these. > > > > > I've ordered more copper clad boards & more stuff on eBay, I hope to > > > receive > > > > > them this week so I can build this upcoming board next WE. > > > > > Lets hope the next one will be the final one for Jaluino Medium > > > > homebrew > > > > Don't worry for me about building many boards, I expected this, and this > > > is > > > a mandatory and very important step. (and I need to see it for real to > > > figure out what should be modified, etc...) > > > > Cheers, > > > Seb > > > -- > > > Sbastien Lelonghttp://www.sirloon.nethttp://sirbot.org > > > > 2009/8/31 Richard <[email protected]> > > > > > Hello Seb, > > > > > > > Ok, I will only add 3.3V to spare pin of the power connector, but am > > > > > > afraid i will at least need to add 1 via and maybe more :-(. > > > > > > Do you mean it would be simpler if you put 3.3V selection and all the > > > > > whistles about 3.3V ?... :) > > > > > Well, it is quit simple to make +5V selectable between 3.3V and 5V > > > > because the traces dont need to be changed so except for serial > > > > connector (this better stay on 5V) all +5V when selected on 3.3V will > > > > become 3.3V so on power connector that +5V will also become 3.3V > > > > (spare stays unconnected). > > > > > above is easier but if you want the main board on 5V and need only > > > > 3.3V for the shield (and off course dealing with the voltage level > > > > adjustments on the shield) this would be impossible. > > > > > But every time when you need 3.3V on a shield you also want to power > > > > your main board with 3.3V so that you dont have to deal with voltage > > > > level adjustments, well than it is the easiest way. > > > > > In my opinion is 3.3V on the spare pin of the power connector AND 5V > > > > selectable between 3.3V and 5V the most flexible option (but off > > > > course also the most impact on the pcb) > > > > > > OK, I'll try to find one of these. > > > > > I've ordered more copper clad boards & more stuff on eBay, I hope to > > > > receive > > > > > them this week so I can build this upcoming board next WE. > > > > > Lets hope the next one will be the final one for Jaluino Medium > > > > homebrew > > > > > > Cheers, > > > > > Seb > > > > > Greetz > > > > > Richard- Tekst uit oorspronkelijk bericht niet weergeven - > > > - Tekst uit oorspronkelijk bericht weergeven - --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "jallib" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/jallib?hl=en -~----------~----~----~----~------~----~------~--~---
