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Istvan Novak, Principal Signal and
Power Integrity Engineer, Samtec
Istvan Novak is a principal signal and
power integrity engineer at Samtec,
where he works on advanced signal and
power integrity designs. Before joining
Samtec, he was a distinguished engineer
at Sun Microsystems (later Oracle),
working on new technology development
and signal and power integrity designs.
He is a Life Fellow of IEEE and holds
twenty-nine patents, is the author of
two books on power integrity, teaches
signal and power integrity courses, and
maintains a popular website.
Systems are getting smaller and denser, which creates many power-related
challenges. As die shrinking reduces the relative distance between components,
coupling coefficients go up. How we manage power distribution becomes critical:
When we have so many devices in a small area, through-the-air coupling can
sometimes interfere with system functionality. In the "old days," we had the luxury
of putting distance between noise sources and victims. Now, we can rarely do that.
In cases of a single noise source, we may find mitigation relatively easy. When we
have multiple noise sources coming from all sides, however, mitigation becomes a
challenge, and that trend is likely to continue.
Here is an example. We had a packaged DC-DC converter with a typical pin layout:
pins for power input and output, pins for control signals, and a few auxiliary power
connections for bias voltages in the few-milliamperes range. We built a circuit using
good engineering practices, but it did not function properly. We found out that noise
generated by high-current circuitry inside the module was coupling to a low-current
supply pin on the DC-DC converter. This finding was surprising because you typically
When Shrinking Circuits, Pay Attention
to Geometry
"When we have multiple noise sources coming from
all sides, . . . mitigation becomes a challenge, and that
trend is likely to continue."
