FEBRUARY 2019 I DESIGN007 MAGAZINE 65
Further Reading
1. Coonrod, J. "Circuit materials and high-
frequency losses of PCBs," The PCB Magazine,
February 2012.
2. Henninger, T. "PCB Surface Finishes,"
Viasystems presentation.
3. Olney, B. "Effects of Surface Roughness on
High-speed PCBs," The PCB Design Magazine,
February 2015.
Chang Fei Yee is a hardware engineer with
Keysight Technologies. His responsibilities
include embedded system hardware
development, and signal and power
integrity analysis.
depicted in Figure 3 indicate that metal plating
or coating on top of the copper trace reduces
the single-ended characteristic impedance by 1
ohm versus Model A (i.e., bare copper without
plating).
Summary
For the fabrication of PCBs with high-fre-
quency signal routing beyond 5 GHz, the selec-
tion of metal plating is very important. Besides
degradation due to oxidation, hardware design-
ers should also consider the skin effect and
attenuation contributed by the conductivity of
the plating material.
DESIGN007
Figure 2: S21 plots for models listed in Table 2. Figure 3: TDR plots for models listed in Table 2.
In an interview with I-Connect007
Technical Editor Pete Starkey, Robert
Art, global account manager for IMS
materials at Ventec International
Group, discusses future market re-
quirements for thermal management
materials, and the need for a better
understanding of the concept of thermal impedance.
"The market is looking for what it has always looked
for—better thermal performance. In every sales meeting
and discussion with customers and at trade show events,
the engineering community is always looking for better
thermal performance. We continue to push the envelope
when it comes to developing stronger, more reliable robust
Robert Art on the Importance of Thermal Management
dielectrics that can be thinner to reduce thermal imped-
ance and resistance values," says Art.
Another topic in discussion was solder joint reliability.
Art noted that solder joint reliability is a big concern today
for many customers, and not exclusive to the automotive
electronics market. "If you look at our roadmaps, some of
the product offerings we're pursuing not only improve the
thermal performance or peel strength but also the modu
-
lus of the dielectric to make it more conducive to provid-
ing a solid solder joint. Solder joint fatigue is a big issue in
our marketplace today, and that's an area of focus for our
future development," said Art.
To read the full interview, click here.
(Source: I-Connect007)
