More IC Datasheet footprint madness

[BobZ]

Complaints Department (Data Sheet Run Amok…Again):

I just ran into something which I thought might provoke interest or at least some snorts of humor or something. (pretty broad range of expectations, huh?)

I just made a symbol for an LM311 comparator IC. It is supplied by TI and ST; maybe others. I wanted to associate it with a footprint.

I probably cannot assign to TI all blame for footprint naming confusion such as SOIC-8 and SO-8. So I will put that aside. At Digikey it looks like the SOIC-8 is probably the most popular package for this IC, so that is the one that I want.

I already have two different datasheet versions saved in my computer. One is an oldie from National Semiconductor and the newer one is marked

OK; TI: Give me the footprint for the SOIC-8. Here is the marking above the drawings for that package:

Now…I can tell from the body size dimensions that this is probably what I want; those are mentioned in a table on P1. But why not tell me that this one is the SOIC, since that what you call it elsewhere?

I decided to try downloading a datasheet from Digikey. It is this one:

Same information. Ought to be the identical datasheet, right? Well, here is the marking on top of the package drawing page:

Hmm???

[jmk]

Maybe the shorter leads are a cost cutting exercise.

Proof reading Datasheets may also be included in the cuts, unless TI have discovered a new Bridge Rectifier

[BobZ]

Hmm…bridge rectifier? I think I would call that one either a square bridge circulator or a transformer smoker.

[jmk]

I thought maybe it is a way of harnessing more electrons.

“They chase around in circles 'till they eventually get tired and then fall down to the -ve Vout rail”

[m852]

In the picture above there is only the size of the component and no footprint… The size of the footprint will be different anyway
DOC012688377.pdf (2.0 MB)
This datasheet has the required footprint under each case type

[BobZ]

@m852

In the picture above there is only the size of the component and no footprint

Yes…but for my own hand soldered boards I really only care about the package dimensions; I mostly design my own footprints based on the package dimensions. In earlier posts of mine, I have given one or two images of my own footprints with fat corner pads for example. Those make hand soldering easier.

The point is, that when you look at Mouser or Digikey you see package names such as SOIC-8. But the first datasheet does not clearly indicate which package drawing is the SOIC-8. (Yes it can be figured out.)

This earlier one is an example of the datasheet not being designed with the customer in mind…

[m852]

hand soldering is greatly facilitated by a stencil and solder paste or a dispenser … all the recommended values \u200b\u200bof the manufacturer have a common standard, which allows you to avoid marriage … with output mounting it is easier … there are also complex cases, for example, bga where there is nothing to do with a soldering iron … in general, everything is smd parts are designed mainly for automatic assembly and its technology

[magnus0re]

Seems pretty clear to me . Clearly says Plastic Small Outline (aka SOIC). Just lookup JEDEC. Correct me if I’m wrong. (I’m joking here)

But yes. This is lazy and should have gotten caught by their Q.C.

[BobZ]

I am really just b******g and moaning here, but if SOIC is small outline, then what is SO? Is that Big Outline?

[teletypeguy]

Hey Bob: The basic “narrow” soic that is everywhere has a 150-mil (~3.9mm) body width. SO is a pretty squishy name imho (I have seen it used for various sizes) – when you see a part listed as SO it means “look in the datasheet.” The term SOP is similarly non-definitive.

AFAIK, SO came from an old EIAJ Japanese standard and usually means a 5.3mm-wide (~209 mil) body (in the lower pin-count parts). Both the 150-mil and 209-mil parts have 50-mil pin pitch, and you can easily make a footprint that works for both. I have not seen many SO parts though.

https://en.wikipedia.org/wiki/Small_outline_integrated_circuit#SOP