Confused over different types of the same chip

[aorwind]

I haven't bought things before for circuitry, but now I already completed my class for it in high school.

I'm trying to buy component parts for a certain schematic diagram that tells me I should get the following: AD8221

I'm pretty confused over model naming conventions. I've looked at the Analog Devices product list for these two and I found that there are several variations. For AD8221, what would be the difference between the AD8221ARZ and AD8221BR other than just cost and RoHS compliance for AD8221ARZ? The AD8221BR is about $1.30 greater in price (for a package of 1000). Wouldn't a type of compliance to something, RoHS for example, cost more? If so, then what the AD8221BR have that AD8221ARZ doesn't? I would also like to know what REEL and REEL7 is.

Here is the product search link:
https://www.analog.com/en/prod/0,2877,AD8221,00.html

Additionally, since the variation is on packaging(size, form, and composition), there wouldn't be in a circuit incompatibilities of different packagings of the same chip in terms of I/O right?

 

[RadioRon]

The difference between 8221A and 8221B (hence 8221AR or ARZ vs BR) is shown in the electrical specifications tables and mentioned in the feature list on the first page of the data sheet. The B version is guaranteed to a higher performance level on DC parameters like power supply rejection ratio, DC offset and so on. Often we find it necessary to study a data sheet very carefully indeed to find the meanings of some prefixes and suffixes, but ultimately, they are there somewhere on the data sheet.

Typically ROHS compliance costs the manufacturer only a one-time charge to pass through the compliance process and possibly adjust their process or materials used. I'm not sure why this cost isn't passed on to the customer typically, but I believe that the costs are typically not very high, and that customers are not willing to pay extra for this.

REEL and REEL7 refer to the size of component reel the part gets shipped in. When you buy ICs for use in a factory, you buy them on circular reels (like the reels we used to see on reel-to-reel tape recorders) much like a film reel. These are standardized to fit into the various pick-and-place machines that assemble the parts onto the pcb. I don't happen to have links to the reference standards. A quick look at Digikey catalog shows that REEL includes 2500 pieces, while REEL7 includes 1000 pieces, so I believe that REEL7 is probably a 7 inch diameter, which is smaller than the normal ones, called REEL.

 

[3v0]

The sufix often indicates the type of package the IC is in.
On Newark I found a
19M0946 ANALOG DEVICES AD8221ARMZ Instrumentation Amplifier
4.6 V Single-Ended 18 V 8-MSOP

and a
19M8891 ANALOG DEVICES AD8221BR Instrumentation Amplifier
4.6 V Single-Ended 18 V 8-SOIC

he devices will work the same. You can look up MSOP and SOIC on the web if needed.

Do not expect pricing to make a lot of sense. The large sellers are often less expensive. Obsolete and slower parts can be more expensive then better/newer ones.

Parts are packaged on REELs for use in automated board manufacture. The parts are inserted into/onto some sort of carrier tape or a strip of some sort, and the strip is wound on a reel.

 

[aorwind]

Wow, thanks guys for the replies. Everything makes a lot more sense now. I thought that the labels only were all pertaining to just the chip properties themselves. I didn't think pricing could be a bit ambiguous.