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Custom Fuzz Buttons RFQ

Fuzz Buttons® are high performance proprietary trademarked contact pins available ONLY from Custom Interconnects and manufactured ONLY in the USA.

Fuzz Buttons® offer superior value to other contact technologies such as Pogo Pins, Spring Probes, Hyberboloid contacts or even soldering.  This becomes especially evident when requirements such as low signal distortion, high frequency, low insertion force, planarity, shock/vibration resistance, weight and/or extended life come into play.

Fuzz Buttons® are available in a wide variety of diameters and lengths, with diameters ranging from .010" to .500" and lengths ranging from .030" to as long as .500".

Most Fuzz Buttons® we manufacture are intended to address fine pitch contact requirements primarily at the 1mm pitch level, but also can serve applications with as small as a .4mm pitch.   Fuzz Buttons® can mate to virtually any packaging type used in the market today - including PGA, BGA, LGA, CGA, QFN and MCM, as well as any custom packaging that a customer may be employing.  This makes them ideal for use in PCB/PWB interposers, connectors, Test Sockets and chip packaging.

We also manufacture many large format Fuzz Buttons® that can resemble cylinders, slugs, discs, doughnuts and washers.  These are typically utilized for specialized EMI Shielding and/or for compliant high current capable ground pads.  It is also possible to lay small or large Fuzz Buttons® on their sides individually or in an end-to-end configuration to emulate a compliant EMI "bead" or to make a long X-axis or Y-axis connection.


Fuzz Buttons® were first introduced to the electronics marketplace in 1959 and were mainly used in grounding applications.  A later example includes their use as static dissipation pads for IBM computer chassis in the 1980s.  Additional customers and applications began to emerge as Fuzz Buttons® gained popularity in the marketas a highly flexible interconnect design solution.  Soon the military sector took notice and began to utilize them in shock- resistant PCB connectors for missile and satellites.  In the early 1990s, Fuzz Buttons® were miniaturized to address the growing semiconductor test market.  Fuzz Button® test sockets were highly regarded by customers such as Qualcomm, AMD and Texas Instruments, when low signal distortion was especially important during development testing, but also for the high mating cycles required for production testing.

Today Fuzz Buttons® still serve the military and commercial markets in many surprising applications.  You will find them in missiles, satellites, space probes, aircraft, test floors, laboratories, radar arrays, antennas, supercomputers, crash test dummies, automotive production, communications and even packaged inside high-end RF products such as attenuators and amplifiers.  Because they are so versatile, Fuzz Buttons® can be used for DC, VHF, UHF, L, S, C, X, Ku, Ka and Q Bands.

Making a Fuzz Button®

 Fuzz Buttons® are a simple, yet elegant structure - whereby, the signal element and the spring are one and the same.  There are no other moving parts that can cause failure or degrade signal integrity, the Fuzz Button® is the direct mating point.

They are manufactured from a long strand of Gold-plated highly specialized very fine wire (often as fine as human hair) that offers high levels of conductivity, strength and oxidation resistance.   The standard wire material used is a Gold-plated Beryllium Copper alloy (Au/BeCu)- which offers the lowest signal distortion levels, high mating cycle repeatability and excellent stability under shock/vibration..

Fuzz Buttons® are also available in specialty materials, such as Gold-plated Molybdenum (Au/Mo) or non-magnetic Au/BeCu).  These are used in special cases - such as operating states at extremely high current or temperature - or when magnetic properties are of special concern.

Fuzz Buttons® are fashioned from these wires using a highly-guarded process that forms them into individual units of certain diameter and length specs.  The manufacturing process causes the wire to be randomized throughout the Fuzz Button® structure.

This randomization results in some very desirable effects, such as

  • Breaking up of internal induction fields that otherwise would form from a coiled spring
  • configuration
  • Reduced signal path length and skin effect levels
  • Increasing the overall structural integrity and strength of the Fuzz Button®
  • Creating multiple points of contact within the Fuzz Button® itself, an internal "redundancy"

Fuzz Button® Specs

  • Applications: LGA, BGA, PGA, CGA, QFN and more
  • Pitch Capability: .4mm and above
  • Compliance/Travel: 15 - 30% of length / 20% nominal
  • Compression Force: 34 grams
  • Current Capability: 5 Amps Continuous
  • Operating Temp: -60°C to 150°C (customer testing has proven this range very conservative)
  • Typical Mating Cycles: Fuzz Buttons alone up to 5000 cycles/ with Hardhats up to 500,000 cycles
  • Frequency Capability: to 40 GHz in natural state, to 100 GHz with design optimization
  • Cross Talk/Bandwidth: -20dB@10Ghz
  • Insertion Loss S21: -1dB@26GHz
  • Return Loss S11: -20dB@10GHz
  • Inductance: 0.19nH Self / 0.03nH Mutual
  • Capacitance: 0.16pF Ground / 0.008pF Mutual
  • Resistance: <10mΩ
  • Rise/Fall TIme: 50ps / 50ps

Note: Representative values above are for .020" diameter/1mm Pitch, see Technical Data page for more information on other configurations.

Contact Technology Comparison

Areas of Consideration
Pogo Pins
The signal travels on the outside of the structure, increasing signal path length and distortion. Many component parts mean more points of potential failure.
Spring Probes
Often an expensive approach.  Commonly a longer contact height than is optimal. Have a very complex structure meaning more potential points of failure.
Hyperboloid / Hypertac / SuperButton / SuperSpring Contacts
Challenging to assemble into carriers.  Component wires sometimes separate from body during usage. Size is limited to larger pitch/pad configurations. Not intended for high mating cycle applications. Long term reliability may be an issue.
The annealed wire structure often  limits mating cycles. Only offered in a single material choice which limits possible applications. Have just two diameter choices which limits pitch/pad matching.
Fragile in harsh environments such as shock, vibration and high temperatures, prone to cracking. Precision placement equipment is very expensive. Very difficult to remove for part replacement. Often not RoHS compliant due to lead content contamination.
Fuzz Buttons®
Signal travels via shortest path within the Fuzz Button® structure; diminishing distortion, resistance and inductance. Simple single piece architecture means a more reliable contact. When used in conjunction with Hardhats, high mating cycles can be achieved with little signal degradation. Always Lead-Free, DFARS and RoHS compliant.

Fuzz Button® Part Numbering

Click on Image to Download Datasheet WW-DDDLLL

WW = Wire Type
DDD = Diameter (in inches)
LLL = Length (in inches)

Example: 80-020130

Standard Wire Material
80 = Au/BeCu (Gold-plated Beryllium Copper)
Most popular due to best S-parameters, lowest
resistance, lowest compression force, best choice for Fuzz Button® diameters of .015" and larger

Other Wire Materials
81 = Au/Mo (Gold-plated Molybdenum)
Great dimensional stability and electrical specs, slightly stiffer wire
- best for Fuzz Button® diameter of 010"

Non-Magnetic Wire
(No Nickel) for Specialized Applications
e.g Quantum Physics Computing and Particle Accelerators
*Specialty Wire Fee Cost Applies*

87 = Au/Mo for .010" to  .062" Diameter Fuzz Buttons

88 = Au/BeCu for .020" to .062" Diameter Fuzz Buttons

.010", .015", .020", .025", .030", .038", .040", .045",
.050", .062", .075", .080", .090", .125", .150", .170",
.200", .250", .280"

For custom diameters, please contact factory

Available ranges shown for each diameter
.010" = .040" to .060"
.015" = .040" to .100"
.020" = .040" to .150"
.025" = .040" to .175"
.030" = .040" to .225"
.038" = .040" to .250"
.040" = .040" to .250"
.045" = .045" to .250"
.050" = .050" to .250"
.062" = .062" to .300"
.075" = .075" to .300"
.080" = .080" to .300"
.090" = .090" to .300"
.125" = .060" to .300"
.150" = .060" to .500"
.170" = .060" to .500"
.200" = .060" to .500"
.250" = .060" to .500"
.280" = .060" to .500"

Fill Rate (approximation)
.010" and .015" diameters = 38%
.020" and greater diameters = 25%

Diameter -5%/+10% (exceptions are .010"/.015" dia)
Length -0/+20%
Fill +/-3%
For custom tolerances, please contact factory.

Fuzz Buttons are to be measured in the uncompressed state and measured with digital calipers that capture the main body structure
of the Fuzz Button between the blades. Optical comparometers should not be used as they give false readings due to the randomized wire forming process. What counts most is AFTER the
Fuzz Button® has been compressed during usage, whereby the amount of material filling the holes remains very consistent across the array. Secondly, Fuzz Buttons® have a large range of
acceptable travel and compliance, they can solve many stackup tolerance and board/packaging planarity issues.

Click on Image to Download Datasheet Applications: PCB Interposers, Device Interposers, Production Sockets, Test Sockets, Connectors, RF / Coaxial
Interconnects, compliant grounding/shorting plates and
internal packaging grounds.

Click on Image to Download Datasheet Large Format Fuzz Buttons®
Applications: Compliant grounding, specialized EMI Shielding and as Static Dissipation Pads. 

Click on Image to Download Datasheet Fuzz Buttons® installed into PTFE/Teflon sleeves for RF/Coaxial interconnect applications providing superior isolation and signal integrity by preventing cross-talk.