Post by thread:[EE]: Analog Mux

I've been poring over Digikey's website for some time now, searching for a solution to this problem. I need an analog multiplexer that should meet these three criteria, in order of importance: 1. Handle 20Vp-p. 2. Be controllable by 5V logic. 3. Be somewhat inexpensive. 4. Be readily available. I don't really want to end up paying $7-$8 for each of them, which rules out a lot of the front-runners, and the readily available rules out many others. Currently I'm looking at the MAX308, but I'm shying away from it's price tag and the fact that no one seems to have it in stock in a DIP package. I've considered scaling the input using a voltage divider if I must, to keep costs down. The rack this is going to be mounted in has ready access to a +/- 12V regulated power supply, so power isn't much of a problem. Anyone have any thoughts, or favorite products that might meet my (ridiculous?) demands? Mike H. _________________________________________________________________ Tired of slow downloads? Compare online deals from your local high-speed providers now. https://broadband.msn.com -- http://www.piclist.com hint: To leave the PICList spam_OUTpiclist-unsubscribe-requestTakeThisOuTmitvma.mit.edu

No immediate answer, but can you reduce / shift the signal, pass it through a 4051 / 4052 / 4053 and then shift back / amplify again? Kind of desperate solution (and not very "space saving"), but if you can manage the errors (drifts / offsets) of the op-amps, this would be a cheaper idea. Francisco Mike Hord wrote: {Quote hidden}> I've been poring over Digikey's website for some time now, > searching for a solution to this problem. I need an analog > multiplexer that should meet these three criteria, in order > of importance: > > 1. Handle 20Vp-p. > 2. Be controllable by 5V logic. > 3. Be somewhat inexpensive. > 4. Be readily available. > > I don't really want to end up paying $7-$8 for each of them, > which rules out a lot of the front-runners, and the readily > available rules out many others. Currently I'm looking at the > MAX308, but I'm shying away from it's price tag and the fact > that no one seems to have it in stock in a DIP package. > > I've considered scaling the input using a voltage divider if I > must, to keep costs down. The rack this is going to be > mounted in has ready access to a +/- 12V regulated power > supply, so power isn't much of a problem. Anyone have any > thoughts, or favorite products that might meet my (ridiculous?) > demands? > > Mike H. > > _________________________________________________________________ > Tired of slow downloads? Compare online deals from your local high-speed > providers now. https://broadband.msn.com > > -- > http://www.piclist.com hint: To leave the PICList > .....piclist-unsubscribe-requestKILLspam@spam@mitvma.mit.edu > > . > -- http://www.piclist.com hint: To leave the PICList piclist-unsubscribe-requestKILLspammitvma.mit.edu

I'm beginning to think that's the only solution. I may even be able to avoid rescaling the signal, since the output is going to be fed to an oscilliscope so it can be observed by human eyes for empirical "quality control". Thanks for the input! Mike H. >No immediate answer, but can you reduce / shift the signal, pass it >through a 4051 / 4052 / 4053 and then shift back / amplify again? > >Kind of desperate solution (and not very "space saving"), but if you can >manage the errors (drifts / offsets) of the op-amps, this would be a >cheaper idea. _________________________________________________________________ Make your home warm and cozy this winter with tips from MSN House & Home. http://special.msn.com/home/warmhome.armx -- http://www.piclist.com hint: To leave the PICList .....piclist-unsubscribe-requestKILLspam.....mitvma.mit.edu

Mike Hord said: > I've been poring over Digikey's website for some time now, > searching for a solution to this problem. I need an analog > multiplexer that should meet these three criteria, in order > of importance: > > 1. Handle 20Vp-p. > 2. Be controllable by 5V logic. > 3. Be somewhat inexpensive. > 4. Be readily available. I've always used the DG201 for situations like that, it's dirt cheap, available, operates with TTL logic from +-15 supplies. Caveat: it's a quad analog switch, not a multiplexer, so you'll have to do your own decoding. -Bob -- http://www.piclist.com hint: To leave the PICList EraseMEpiclist-unsubscribe-requestspam_OUTTakeThisOuTmitvma.mit.edu

*IF* you are ONLY using the output to drive an oscilloscope for waveform quality to be examined by eye then a scaled down version using a common as dirt and twice as cheap CD4051 family transmisison gate will work superbly. The CD4051 family has the ability to switch +5/-10 signals with appropriate supplies using only 0/+5 signals AFAIR BUT you will not need this capability. Simply level shift and scale down, quite probably using resistors alone, and use a CD405x. Summary: There will come a point where the CD405x is not up to spec but it should handle this application as stated with ease. Russell McMahon -- http://www.piclist.com hint: To leave the PICList RemoveMEpiclist-unsubscribe-requestTakeThisOuTmitvma.mit.edu

>Mike, > >Sorry this is off list but I haven't set up my email at work to broadcast >the right address for the piclist. If I reply here it bounces me... No problem at all... >The MAX308 is an improved version of the venerable DG508A and its kin. >Unless you need some of the improved specs of the MAX308 you should be able >to find DG508s all over the place. I will look into it, as I will into the other products recommended by all of you. I will also expand beyond Digikey. At this point, having further discussed it with the end user (one person), I'm probably going to divide by two the signal and use a 4051, unless I can find another product that will work well for a similar low price. >Try Siliconix/Vishay for a DG508A family data sheet (Google should help) >then http://www.findships.com to check for stock. Siliconix/Vishay don't seem to do much with Digikey, which is probably why I missed them. I still prefer Digikey's parametric product search capabilities, which is frankly the primary reason I buy through them. >If this works for you please forward this to the piclist. I really gotta >configure my email here! Done! Thanks to everyone who suggested a solution, and especially Bob for directing me to Mouser for a cheaper source on the DG201. I'm just now starting to compare prices between Digikey and Mouser on all products, and the difference can sometimes be surprising! Mike H. _________________________________________________________________ Tired of slow downloads? Compare online deals from your local high-speed providers now. https://broadband.msn.com -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads