On Board Fiducials:

Quick guidelines we use -
	1. Place them in all four corners of board. At least 2 diagonally.
	2. There are light fiducials or dark fiducials -
		Light fiducial is 50 mil pad (typically used) with a 20 mil min.
			non-interference area (via and etch keepout)
		Dark fiducial is a "donut shape" where the "hole" of the donut
			is 50 mils and the "donut" is 20 mils.
	3. Brd Fiducials should be placed on both top and bottom of the board.
	4. Fiducials should not be covered with soldermask. ( 100 mil opening min.)

*Any circular pads (i.e. vias, component terminals, etc.) that are between .040 - .070
	should be kept .200 away from fiducials, OR changed to be a square pad
	so that the vision system (or the operator - not sure why) doesn't "see" the
	wrong pad. 

I haven't connected them to gnd - we leave them as brd symbols. No problems or requests
to do that.

As a rule, we keep them approx 200 mils in from the edges of the board - or align them
with existing mtg. holes.

Tom Kavendek
Lucent Technologies
700 Mountain Ave.
Murray Hill, N.J. 07974
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