----- Begin Included Message -----
From: Mitch Morey <[log in to unmask]>
We (internally)have a growing debate going on in regards to reference
designators. We have (long ago) adopted IEEE 315 as the "bible" for
schematic symbol and reference designators, but the standard seems
misleading.
Take for instance OP-AMPs should have "AR" as the designations,
OSCILLATORS should be "G", ATTENUATORS should be "AT" according
to how you interpret the standard.
But, aren't these all, in fact, microcircuits ("U") or integrated-circuit
packages in today's practice? Does anyone else have a better system
for defining reference designators, per "some" standard? It seems IEEE-
315/315A should have been out-dated long ago.
Help?
Mitch
----- End Included Message -----
Mitch,
As a (used to be) drafting checker, this subject always was a favorite
of mine. In selecting which reference designation class letter, one should use
the following algorithm:
Is there a specific class letter? AR, AT, G in your query. If so then
use it.
If ther is no specific class letter, is the component normally
disasseble-able without damage? If yes, use A, if no use U. U is not
a specific class letter for microcircuits but most microcircuits
do not have specific class letters and can not be disassembled without
damage thus the use of U.
|
/|\
/ | \
/ |__\ /\
/____@_\ |
~~[________)~~
~~~~~~~~~~~~~~[]~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Michael L. (Mike) Holmes
Charter Member, Space Coast Chapter, IPC Designers Council
MS 1-5852
Designer 3 Harris Corporation
PWB Design Group Government Communications Systems Division
Digital and Electronic 2400 NE Palm Bay Road
Packaging Section Palm Bay, FL 32905
*****************************************************************************
################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe: SUBSCRIBE TechNet <your full name>
To unsubscribe: SIGNOFF TechNet
################################################################
Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################
|
