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EMI filter connectors, quite frankly, can
be a pain. No one designs a system
around a connector, so often by the
time EMC is considered there is very
little space left for traditional, bulky
filter connectors. Another problem is
design flexibility: achieving sufficient
EMI noise protection may often require
the system to be fully developed
before the problem can be accurately
assessed, and any last minute system
changes may require a complete
rethink. Ceramic filter arrays that
are inserted into specially-adapted
connector shells can take weeks
to arrive, since they are all custom
parts. They are also expensive and
fragile. Worse, retrofits are difficult
to achieve, since adding EMI filtering
almost always requires a complete new
connector body - assuming you have
room enough to accommodate the
extended connector length.
A new, ingenious solution looks set
to confine bulky, expensive ‘kludged’
filter connectors to the electronics
industry’s museum of horrors, as
Quell - a 20 year old company based
in Albuquerque, USA - has invented
a new, simple retrofit EMI connector
technology which is deliverable in
under one week, and which can be
retrofitted into existing connectors very
simply, even in the field, providing an
effective EMC solution that will survive
extreme environmental abuse. The
technology can also be used to provide
surge suppression.
Quell’s EESeal
®
technology uses filter
components - resistors and capacitors
- embedded into a silicone rubber
insert that matches the size, shape
and pin configuration of the connector
required to be filtered. Users specify
which EMI filter elements, if any,
are required for each pin. To ensure
integrity of connection, all external and
internal wiring is fully plated with 50-70
microns Au over Ni flash. The custom
inserts are easily and quickly inserted
into standard connector bodies,
without the need for any special tooling
or soldering, forming an effective EMI
filter and an environmental seal.
EESeal’s unique elastomeric body
and adaptive interconnect system
suspends, isolates and protects the
discrete electrical components. This
allows the entire assembly to change
shape in response to external forces
without compromising the filtering
or the electrical and mechanical
integrity of the system. The silicone
body acts as a conformal coating and
electrical isolation for the components
suspended within it, and the natural
compressive forces are exploited to
create re-usable, electrical contacts
that can withstand extreme abuse
(severe misalignments, vibration,
wrong pin sizes). Importantly, EESeal’s
also create an environmental seal.
Since EESeals do not use a PCB or
planar ceramic array construction,
they offer major advantages when
The Perfect EMC Connector Design Solution?
Gary Evans, Astute Electronics
Connectors & Cables
Special Edition
62 l New-Tech Magazine Europe