Chapter 1
User Interface
©
National Instruments Corporation
1-23
Through Hole Pad Annular Ring
Footprints in the database have been designed with pad sizes in accordance
with the manufacturers’ recommendations. To change these settings you
can edit the footprint in the database or directly on the design using the
In-place Part Edit
command. Alternatively, you can apply a set of design
rules to specific footprints or to the entire design.
The annular ring setting (the ring of copper around the drill hole of a pad or
via) allows you to specify either a fixed value (for example, 50 mils) or a
relative value that depends on the radius of the drill hole size. For example,
a 50 mil drill hole (radius of 25 mils) with a relative value of .6 (60%) will
create an annular ring of 15 mils (60% of 25 mils). When using relative
settings, it is important to choose minimum and maximum values to ensure
that the annular ring will never go beyond those bounds.
Complete the following to enter an annular ring setting:
1.
Click the button beside the desired field (
Top
,
Inner
or
Bottom
) in the
Pad/Vias
tab. The
Through Hole Pad Properties
dialog box appears.
Choose
Fixed
and enter the fixed value.
Or
Choose
Relative
and enter the relative setting. Be sure to choose
Min
and
Max
values.
Complete the following to apply the design rules to a footprint:
1.
Select the footprint and choose
Edit»In-Place Part Edit
.
2.
Select the pads to which the rule should apply.
3.
Right-click and, from the context menu, choose
Properties
.
4.
On the
Pad
tab of the properties dialog box, enable
Use Design Rules
.
Vias
The
Vias
setting sets the default
Drill Diameter
and
Pad Diameter
to be
used when a via is placed during trace placement. This setting also applies
to vias that have already been placed in the design.
Microvias
The
Micro Vias
area is where you set the default via dimensions to be used
when a microvia is placed during trace placement. This setting will also
apply to microvias that have already been placed in the design.
