Pin pitch of MSOP package?

[treez]

Hello,
Why do MSOP packages sometimes have a 0.5mm pin pitch, and sometimes a 0.65mm pin pitch?
Surely, and "MSOP" package must always have a certain single pin pitch?

For example of differences....
LTC1871 comes in 10MSOP and has 0.5mm pin pitch
http://cds.linear.com/docs/en/datasheet/1871fe.pdf

MCP6L92T-E/MS comes in 8MSOP and has a 0.5mm pin pitch
**broken link removed**

Is one of the above datasheets in error regarding pin pitch?

 

[jpanhalt]

Apparently, the 0.5 mm and 0.65 mm versions are well known (https://en.wikipedia.org/wiki/List_of_electronics_package_dimensions) and appears to correlated with the number of pins. If know the reason is important, looking up the relevant standard is probably the best way.

Several years ago, I made a PCB with what I thought was a "standard" SOIC pad arrangement. My part did not fit well (pitch was OK, separation along the long axis wasn't). When I checked the datasheet for my part, I found it was different. Since then, when dealing with SMD IC's , I always go the the actual datasheet to be sure the pads are proper.

John

 

[marce]

That is why we have the IPC-7351 specification and naming convention...
Look up "The CAD library of the future"
Names such as MSOP, TSOP etc have no defined relationship to pin pitch and never have done.