Gail,

Being a small contract manufacturer, we see a wide variety of boards from an
equally wide range of vendors, designers, etc.  While there may be a
standard for where the 'square pad' should be used (I'm not aware of it), it
appears from our end that it isn't adhered to. We see square pads on the
cathodes of diodes, the '-' leads of electrolytic caps, the '+' lead of
tantalum caps, etc.  I've also seen IC land patterns where pin 1 is round
and all other pads are square.

As for the body markings on diodes, I believe JEDEC http://www.jedec.org/
has specific recommendations for these.

Rick Thompson

-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Gail Herman
Sent: Thursday, July 30, 1998 1:49 PM
To: [log in to unmask]
Subject: [TN] Diode Polarity


Hi,   This is the first time I have used the Technet forum . I'm hopeful
that
there is some information out there to help me with the following questions.
Thanks in advance for your help!!!!
1) standards for polarity identification of  axial-leaded and chip style
diodes
on the component body and how does this correlate to '+'  and/or square land
on
the board .
2) square lands used to indicate polarity  as in pin1 or 'positive'  ;  is
this
an industry standard? Does a silkscreen '+' have precedence over the square
land as a Pin1 indicator?

I look forward to responses from the forum!

Thank you,


Gail Herman
    LPAT Process  Technician
    433(293)-6395 pager 487-4964
   [log in to unmask]

################################################################
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's web site (http://www.ipc.org) "On-Line Services" section
for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or
847-509-9700 ext.312
################################################################

################################################################
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's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################