Do not forget that some CAD packages will provide sample Libraries of
Symbols and Patterns for 'free'. I have found these to have errors - like
Diodes with the Anode as Pin '1'.
One instance where diodes get their Pin 1 assigned to Anode is when it gets
to Spice simulation (correct me if I am wrong).
Assigning Pin 1 to Cathode should be a rule that is written down -
followed - and pretty much enforced. Otherwise, it causes confusion later,
during assembly and troubleshooting.
Regards,
James Jackson
Oztronics
-----Original Message-----
From: DesignerCouncil [mailto:[log in to unmask]]On Behalf Of
Patrick Jabbaz
Sent: Monday, March 19, 2007 10:22 PM
To: [log in to unmask]
Subject: Re: [DC] Footprint standards for Polarized components (Diodes)
Gary,
This is a very common problem,
As far as I understand pin 1 is cathode, however some manufacturers have
Pin 1 as anode, and to make matters worse, the same manufacturer will
have pin1 as anode for one device and pin1 a cathode for a different device.
What I do is to make all foot-print for diodes having pin 1 as cathode
where the marking is, and tell all engineers to always use this rule,
regardless of the data sheet, any way we also revised data sheets
indicating pin 1 as cathode.
It is better for this to be ironed out by the designated librarian and
component engineer, and make this as a rule.
-Patrick
Gary Bremer wrote:
> Hi,
> I have been asked if there is a standard for creation of footprints
> espicially for diodes. One of the designers reversed the cathode and
> anode causing all the diodes to be placed backwards. The rational was
> the pin 1 was the anode for this device for other diodes pin 1 is the
> cathode.
>
>
> Gary Bremer CID
> Manufacturing Engineer
>
> _________________________________________________________________
> Exercise your brain! Try Flexicon.
>
http://games.msn.com/en/flexicon/default.htm?icid=flexicon_hmemailtaglinemar
ch07
>
>
> --------------------------------------------------------------------------
-------
>
> DesignerCouncil Mail List provided as a free service by IPC using
> LISTSERV 1.8d
> To unsubscribe, send a message to [log in to unmask] with following text in
> the BODY (NOT the subject field): SIGNOFF DesignerCouncil.
> To temporarily stop/(restart) delivery of DesignerCouncil send: SET
> DesignerCouncil NOMAIL/(MAIL)
> Search previous postings at: www.ipc.org > On-Line Resources &
> Databases > E-mail Archives
> Please visit IPC web site
> http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional
> information, or contact Keach Sasamori at [log in to unmask] or
> 847-615-7100 ext.2815
> --------------------------------------------------------------------------
-------
>
>
--
Patrick Jabbaz
Ubiquiti Networks
495-499 Montague Expwy
Milpitas, CA 95035
T: (408) 942-3085
M: (408) 621-6533
----------------------------------------------------------------------------
-----
DesignerCouncil Mail List provided as a free service by IPC using LISTSERV
1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF DesignerCouncil.
To temporarily stop/(restart) delivery of DesignerCouncil send: SET
DesignerCouncil NOMAIL/(MAIL)
Search previous postings at: www.ipc.org > On-Line Resources & Databases >
E-mail Archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16
for additional information, or contact Keach Sasamori at [log in to unmask] or
847-615-7100 ext.2815
----------------------------------------------------------------------------
-----
---------------------------------------------------------------------------------
DesignerCouncil Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF DesignerCouncil.
To temporarily stop/(restart) delivery of DesignerCouncil send: SET DesignerCouncil NOMAIL/(MAIL)
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
---------------------------------------------------------------------------------
|
