Surface-mount Fuses0 pages

Surface-mount Fuses – Fundamentals

Surface-mount Fuses
Fundamentals
Overview
TE Circuit Protection offers the widest selection of surface-mount
fuses available for addressing a broad range of overcurrent
protection applications. Helping to prevent costly damage and
promote a safe environment for electronic and electrical
equipment, our single-use chip fuses provide performance stability
to support applications with current ratings from .5A up to 20A.
TE Circuit Protection also offers the telecom FT600 fuse for
telecommunications applications. This telecom fuse helps comply
with North American overcurrent protection requirements,
including Telcordia, GR-1089, TIA-968-A (formerly FCC Part 68),
and UL60950 3rd edition.

Multi-layer Design for Chip Fuses
The multi-layer design has the benefit of exposing more fuse
element surface area to the glass-ceramic absorption material.
When the fuse elements open, there is more material for the
vaporizing fuse metals to absorb into, resulting in a very efficient
and effective quenching of the fuse arc.
Figure 1 compared the multi-layer design of our SFF fuses with
standard glass coated designs. The glass coated designs rely on
the coating on only one side of the fuse element to absorb the
vaporizing fuse material when it opens. Therefore, there is much
less absorption material available to absorb the fuse metals. The
result can be prolonged arcing and possible coating breach.
Figure 2 shows how the absorption characteristics of the two
designs differ. The multi-layer design indicates a clean separation
with the fuse element evenly diffusing into the surrounding
ceramic substrate. In the glass coated design, the element
diffusion takes place in a small portion of the device and is only
absorbed by the glass material directly above the area of failure.

Figure 1
Glass/Ceramic
Substrate

Multiple Fuse
Elements

Multi-layer Design

Substrate
Material

Single Fuse Glass
Element Coating

Single-layer Glass Coated Design

Figure 2
Fault Zones

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Multi-layer Design

Single-layer Glass Coated Design

Wire-In-Air Design for 2410SFV Fuses
The 2410(6125) is a Wire-In-Air SMD Fuse which is very suitable
for secondary level over current protection applications.
Figure 3 compared our straight wire element design 2410SFV
fuses with normal corrugating wire design fuse. The straight wire
element in air performs consistent fusing and cutting
characteristics together with excellent inrush current
withstanding capability.
Introduced PCB assembly technology into 2410SFV fuses design
and manufacture, we achieved on lead free completely and no
end cap falling off risk comparing with traditional ceramic body
with end cap fuse.

Figure 3
Glass fiber enforced
epoxy body

Straight wire element

Copper terminal
plated with Ni and Tin

Ceramic body
Corrugate wire element
End cap plated with Tin

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