Post by thread:[PIC:] MAX232 Capacitors???

Hiya, The Maxim datasheet says use 1.0uf external caps on their MAX232 part and use 0.1uf caps with their MAX232A part. Everyone in the world seems to specify 10uf for the MAX232. Any idea which is correct? Thanks! -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

I use 1.0uf caps with the MAX232. I've built literally hundreds of them and never run into problems even above 100k baud. Quoting Matt Redmond <spam_OUTmdredmondTakeThisOuTCHARTER.NET>: {Quote hidden}> Hiya, > > The Maxim datasheet says use 1.0uf external caps on their MAX232 part and use > 0.1uf caps with their MAX232A part. > > Everyone in the world seems to specify 10uf for the MAX232. > > Any idea which is correct? > > Thanks! -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

This is the old case of the missing "point" ... ;-)) Mark Jordan On 27 Apr 2004 at 17:33, Matt Redmond wrote: {Quote hidden}> Hiya, > > The Maxim datasheet says use 1.0uf external caps on their MAX232 part and use 0.1uf caps with their MAX232A part. > > Everyone in the world seems to specify 10uf for the MAX232. > > Any idea which is correct? > > Thanks! > > -- > http://www.piclist.com hint: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

The 'A' version of the chip has a higher frequency osc and therefore can use smaller caps , 0.1uf. The non-'A' version of the chip needs 1uf minimum, but others recommed 10uF since if gives the chip higher output current driving capability. I've used 1uF on all my stuff for years without problems, though there was a time I 'forgot' what value I was supposed to use, bought 1000 qty 10uF caps and used those instead. The 'A' part and the non-'A' part are NOT the same part! Dave ----- Original Message ----- >The Maxim datasheet says use 1.0uf external caps on their MAX232 part and use > 0.1uf caps with their MAX232A part. -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

> The Maxim datasheet says use 1.0uf external caps on their > MAX232 part and use 0.1uf caps with their MAX232A part. I don't, I always use 1 uF. Smaller and cheaper. > Everyone in the world seems to specify 10uf for the MAX232. IIRC there is a load/voltage graph somewhere in the datasheet. You can use it to determine what cap you need. I think even the vanilla MAX232 will work with 100nF under some circumstances. Wouter van Ooijen -- ------------------------------------------- Van Ooijen Technische Informatica: http://www.voti.nl consultancy, development, PICmicro products -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

I use the .1uf on the 232A. Although the 232A is a bit more expensive, the caps are cheaper and the price difference is neglible when you include the caps. The 233 doesn't require any caps... but the part is more expensive. The choice factor for me is all in how many units you will produce. Mike *********** REPLY SEPARATOR *********** On 4/27/2004 at 5:33 PM Matt Redmond wrote: {Quote hidden}>Hiya, > >The Maxim datasheet says use 1.0uf external caps on their MAX232 part and >use 0.1uf caps with their MAX232A part. > >Everyone in the world seems to specify 10uf for the MAX232. > >Any idea which is correct? > >Thanks! > >-- >http://www.piclist.com hint: The list server can filter out subtopics >(like ads or off topics) for you. See http://www.piclist.com/#topics -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

the 'E' is for extended ESD protection to 15KV I believe. -----Original Message----- From: pic microcontroller discussion list [.....PICLISTKILLspam@spam@MITVMA.MIT.EDU]On Behalf Of Igor Pokorny Sent: Wednesday, 28 April 2004 6:18 AM To: PICLISTKILLspamMITVMA.MIT.EDU Subject: Re: [PIC:] MAX232 Capacitors??? If you need to feed anything else from MAX232 chip you better use 10 uf... BTW I thought chips ending by 'E' are allowed to use 0.1 uf caps only. -----Original Message----- From: pic microcontroller discussion list [.....PICLISTKILLspam.....MITVMA.MIT.EDU] On Behalf Of Matt Redmond Sent: Tuesday, April 27, 2004 7:34 PM To: EraseMEPICLISTspam_OUTTakeThisOuTMITVMA.MIT.EDU Subject: [PIC:] MAX232 Capacitors??? Hiya, The Maxim datasheet says use 1.0uf external caps on their MAX232 part and use 0.1uf caps with their MAX232A part. Everyone in the world seems to specify 10uf for the MAX232. Any idea which is correct? Thanks! -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Matt Redmond <mdredmondspam_OUTCHARTER.NET> wrote: > The Maxim datasheet says use 1.0uf external caps on their MAX232 part and > use 0.1uf caps with their MAX232A part. > > Everyone in the world seems to specify 10uf for the MAX232. > > Any idea which is correct? As always, it depends. For a discussion of some of the theory, see the Circuit Cellar EQ for issue #156, in particular, problem #3: http://www.circuitcellar.com/library/eq/156/index.htm -- Dave Tweed -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Be careful with the non-cap parts (Max233). I've seen heavy RF radiation from the output pins, particularly if the device is not VERY heavily bypassed. Can be a costly surprise. --Bob Michael J. Pawlowsky wrote: > The 233 doesn't require any caps... but the part is more expensive. > The choice factor for me is all in how many units you will produce. -- Replies: NOTE-Script, EXE,BAT and COM files will be rejected by server -------------- Bob Axtell PIC Hardware & Firmware Dev http://beam.to/baxtell 1-520-219-2363 -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

I have been working on industrial single board computers and PLCs for the last couple of years now and I can tell you most every MAX232 that I see has 10uf caps. I have even seen a mix of 15uf and 22uf caps being used.. They do seem to work but they don't seem to be following maxims suggestions.. ----- Original Message ----- From: "Peter Moreton" <@spam@peterKILLspamRIL.ORG.UK> To: <KILLspamPICLISTKILLspamMITVMA.MIT.EDU> Sent: Tuesday, April 27, 2004 5:02 PM Subject: Re: [PIC:] MAX232 Capacitors??? > I use MAX232CSE's (ie: ending in 'E') with 1uf cap's, and they work just > fine, even in noisy automotive environments. > > > {Original Message removed}

I've built literally hundreds (maybe over a thousand?) of the MAX232 (not 232A) circuits using 1uF caps, and I don't have any problems. I've used mostly the TI version, but I've also used Maxim and ? someone else's chip, I'm drawing a blank now. The TI datasheet recommends 1uF caps, BTW. Steve {Original Message removed}