72 Silicon chip Australia’s electronics magazine siliconchip.com.au
Fig.5: using Follow Mode on the lower track produces a
neater result and allows better use of board space.
Fig.6: the Impedance tab of the advanced Layer Stack
Manager provides the option to fine-tune track impedance
and other characteristics for both single-ended and
differential tracks.Fig.7: the Dielectric Shapes Generator dialog box gives
an idea of how some types of printed electronics can be
fabricated, using minimal areas of dielectric material
which are used to separate conductors that would
otherwise produce a short circuit.
Fig.8: the Multi-Board Assembly tool can be used to see
how a design composed of multiple components, including
PCBs and other parts, comes together as a whole. Here we
have combined four copies of our Stackable LED Christmas
Tree with the USB Digital Interface board.than before. It will now more reliably detect if the track
has looped back upon itself, and close the loop to shorten
the track. Sometimes you don’t want that, though, so that
feature can also be turned off in Preferences.
Advanced Layer Stack Manager
We do not use the Layer Stack Manager to any great ex-
tent as our designs typically have only two layers on stand-
ard FR4 substrate (with a couple of four-layer exceptions),
and usually don’t have any special requirements regarding
high-frequency operation. But this new feature would be
useful for those that do have such special requirements,
such as with many RF boards.
The new version of the Layer Stack Manager uses a ma-
terial library to keep track of which material characteris-
tics (such as copper weight and dielectric thickness and
other properties) can be used on a given PCB. The layer
stack can then be assembled from the library of known
materials.
This allows customisation of the board’s impedance
characteristics, for both single conductors and differen-
tial pairs. Given accurate material information, the Im-
pedance tab allows quantities such as impedance, prop-
agation delay, track inductance and track capacitance to
be easily calculated.
An example of the result of these calculations being
displayed is shown in Fig.6. This dialog also shows how
the software uses the stack material data to calculate the
dimensions for laying tracks with a controlled impedance
for differential signalling.Printed electronics support
One of the more unusual ways of creating circuits is the
use of printed electronics. This involves printing conduc-
tive layers on an insulating substrate to build up the cir-
cuit, rather than the more traditional method of removing