Elastomeric Connectors Unlock Design Creativity
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Tyco Electronics provides a very low resistance elastomeric connector product: STAX LD connectors from the Elastomeric Technologies (ETI) product line. Over the years, ETI has honed their core competencies of conductive particle loading, laminating and cutting. The result of all this experience and effort is the STAX LD connector line, a technology that provides stable low resistance over a wide deflection range and under harsh environmental conditions. |
Elastomeric connectors have proven their reliability
and diversity over many years and a myriad of
applications. The technology is such that it unlocks
the creativity of designers by allowing quick
creation of economical custom compression connectors
without long lead times and high tooling
charges. Typically, elastomeric connectors consist
of redundant layers of conductive and non-conductive
silicone rubber. These layers are thin and
are typically 0.05mm in thickness, allowing 4 conductive
layers to make redundant contact between
0.5mm wide pads on 1.0mm pitch. At the same
time, 4 non-conductive layers would contact to the
non-conductive space in between contact pads,
thus assuring insulation between adjacent mated
contact pairs.
The STAX LD technology is based upon 30 years of
experience in manufacturing and in the hundreds
of millions of connectors used in trouble-free applications.
This is a low durometer and low contact
resistance product.
The elastomer is a single piece compression technology.
The silicone within the connector provides
the normal force (spring). The conductive layers
(blend of silicone and conductive metal particles)
make redundant electrical contact to the pads on
the board.
The use of silicone creates a sealed connection
between mirror image pad patterns on mating PC
boards or other flat substrates such as flex circuits,
ceramics or digital display glass.
Tyco Electronics maintains complete control over
the quality and performance of the product. The
STAX product line is manufactured from basic raw
materials using a proprietary manufacturing process.
The result is a connector technology that allows
the freedom of design without the traditional
limitations of standard product availability. There
is no need to compromise the end product at the
design stage.
Elastomeric connectors are viable in most applications
where traditional board-to-board connectors
are used. The applications may include high speed,
power, digital, grounding/shielded interconnect.
How Do STAX™ Elastomeric Connectors Work?
STAX™ elastomeric connectors provide a compliant surface-to-surface compression connector when deflected between opposing mirror-image pad patterns as the drawing below illustrates.
STAX™ are composed of alternating layers of conductive and non-conductive silicone rubber. The conductive layers consist of tiny metallic particles embedded in silicone. These layers make redundant compliant connection between mated PC board contact pads.
We chose silicone rubber as the base material because it is inorganic and has excellent aging and stress-relaxation properties. It also doubles as a seal across the contact interface.
Items of note
- Conductive layer pitch as low as 0.13mm (0.005")
- 3 to 4 conductive layers typically contact to 0.5mm wide pads
- 3 to 4 NON-conductive layers typically separate adjacent 0.5mm wide pads on 1.0mm centers cone base material provides excellent aging properties
- Compliant compression connector that provides gasket seal over contact area
- Shock and vibration are inherently dampened
When Is It Best to Use STAX Elastomeric Connectors?
In volume manufacturing of space-constrained electronic products such as cell phones, pagers, person digital assistants, disk drives, personal entertainment devices, etc.
The chart below shows the application scenarios where elastomeric connectors work best.
In this chart:
- Pad pitch is shown on the X-axis
- Board-to-board spacing is shown on the Y-axis
- Mating surfaces must be properly aligned to allow for sufficient pad-to-pad overlap area to assure good contact
- The shorter the elastomer height, the tighter the pitch attainable
Can they connect to fine pitch - Elastomeric Technologies?
Yes. It is important that the mating pad patterns are properly aligned to allow for enough pad-to-pad overlap area to assure good contact. To prevent shorting, one also needs to account for the conductor skew and maximum layer thickness within the STAX connector. Generally speaking, the shorter the STAX connector height, the tighter the pitch attainable.
When do I NOT want to use a STAX elastomeric connector?
In situations such as: Testing, prolonged exposure to very high temperatures (at or above +1250ºC), low production volume (due to customization), and places where they could be subjected to hydrocarbons or chlorinated solvents.
What PC board pad metals should be used - Elastomeric Technologies?
STAX elastomeric connectors work best on gold pads. In an office environment, they also work very well with hot-air-leveled tin-lead pads. If you have an alternative pad metal that you would like to use, consult Tyco Electronics Elastomeric Technologies. In all cases, do not place solder mask in the STAX connector PC board footprint as it may interfere with connection to the PC board pad.
How well do they work under shock, vibration and harsh environments - Elastomeric Technologies?
Very well. The elastomer creates a gasket-like seal across the connection. The base material is silicone rubber which inherently dampens shock and vibration. Test data is available through Tyco Electronics, Elastomeric Technologies.
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