Re: gEDA: Component Packages and PCB Land Pattern - naming Conven tions

[Steve Meier]

Here is an argument to move the Land Pattern naming convention from 
IPC-SM-782A "Surface Mount Design and Land Pattern Standard" (first 
published August 1993 last updated in April 1999) to IPC-7351 "Generic 
Requirements for Surface Mount Design and Land Pattern Standard" 
(Proposed Standard for Ballot October 2004)

JEDEC has a package they refer to as MO-153  this is sometimes refered 
to as TSSOP. There exist devices which use this package,

Basically it is a package with gull wing leads on two sides with a pitch 
between leads of 0.65mm

For the package MO-153AB wich is a 14 pin version of this package there 
is no defined landpattern in the IPC-SM-782A and thus no Regestered Land 
Pattern Number. The regestered land pattern number being the prefered 
way to name the land pattern for this type of package.

The new standard doesn't require package registrataion instead it has a 
naming convention that allows new packages to be introduced and to have 
meaningfull names created for the packages land pattern.

For example:
JEDEC JEP95  package type:  MO-118AA
Package Description: Shrink Small Outline Package (SSOP) 48 Pins
IPC-782A  Regestered Land Pattern Number:  330A
I think the IPC-7351 name is as follows.
IPC-7351 Name: SSOP63P10-48
IPC-7351 name disected
SSOP
63            0.635mm pitch
10            10.35mm Lead Span  (distance from tip of one lead to the 
tip of the lead on the oposet side of the device)
-                seperator before the pin count
48             for the 48 pins

Steve Meier