Post by thread:[EE]: Why 208 vs 150?

Ok, I'm looking at Microchip's 24LC256 for an upcoming project. For surface mount, there are a number of different options. Personally, I don't really understand TSSOP, at least from the drawings it looks large. I've never seen one in real life, or an actual comparative photo. If anyone knows of some good photos, I'd love to see them. Anyway, I'm looking at SO packages. In this part, Microchip offers an 150mil SO, and a 208mil SO. Is this because of metric vs imperial? Josh -- A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools. -Douglas Adams -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

On Sat, 11 Oct 2003 00:58:55 -0400, Josh Koffman wrote: >Ok, I'm looking at Microchip's 24LC256 for an upcoming project. For >surface mount, there are a number of different options. Personally, I >don't really understand TSSOP, at least from the drawings it looks >large. I've never seen one in real life, or an actual comparative photo. >If anyone knows of some good photos, I'd love to see them. > >Anyway, I'm looking at SO packages. In this part, Microchip offers an >150mil SO, and a 208mil SO. Is this because of metric vs imperial? > Good thought. It certainly looks like that's probably the case. If my math is right: 148 mils converts to 3.75 mm. 207 mils converts to 5.25 mm. Regards, Bob -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Josh Koffman wrote: > Ok, I'm looking at Microchip's 24LC256 for an upcoming project. For > surface mount, there are a number of different options. Personally, I > don't really understand TSSOP, at least from the drawings it looks > large. I've never seen one in real life, or an actual comparative photo. > If anyone knows of some good photos, I'd love to see them. The line card has 1:1 scale pictures of all the packages. It's usually a few pages from the back. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Fantastic! Thanks for the tip Olin. For the record, I still don't get the TSSOP package style. Just seems like the SSOP with the leads on a different side. But at least now I can see the relative sizes. Thanks! Josh -- A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools. -Douglas Adams Olin Lathrop wrote: > The line card has 1:1 scale pictures of all the packages. It's usually > a few pages from the back. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

> Just seems like the SSOP with the leads on a different side Which is very convenient for serpentine track layouts Particularly with devices that have bussed i/o and address lines, like memory or LCD drivers, when between-pin tracks on such small pitch ICs would be impractical or mean many vias, links or extra layers -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Ah...suddenly it makes so much sense. Widen the area that has no pins, and you can get more tracks under the device. Cool! Josh -- A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools. -Douglas Adams Jinx wrote: > > > Just seems like the SSOP with the leads on a different side > > Which is very convenient for serpentine track layouts > > Particularly with devices that have bussed i/o and address > lines, like memory or LCD drivers, when between-pin tracks > on such small pitch ICs would be impractical or mean many > vias, links or extra layers -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email spam_OUTlistservTakeThisOuTmitvma.mit.edu with SET PICList DIGEST in the body