1812J1000682MCTE03 Syfer, 1812J1000682MCTE03 Datasheet - Page 5

• Manufacturer Part Number: 1812J1000682MCTE03
• Description: EMI Filters 1812 .0068uF 100V C0G 20% X2Y Filter
• Manufacturer: Syfer

Specifications of 1812J1000682MCTE03

• Product Category: EMI Filters
• Rohs: yes

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Thread size or head size? What’s the crucial
factor in spacing
The thread size has no relevance to the mounting pitch, but
can influence cost. Very small threads are harder to work
with, but offer little or no gain over larger thread sizes.
If close mounting pitch is important, change instead to a
round body style. Mounted using modified screwdriver blades,
this style of component removes the need to allow space
for mounting sockets and allow components to be mounted
almost touching each other.
Syfer offer a full range of round head filter types - SFNO,
SFKB, SFKK, SFLM, SFMD and SFUM. Special requirements
can also be considered.
Schematic showing the pitch improvement that can be gained
with round head filters compared to traditional hexagon heads
Hermetic seals vs resin seals
Resin sealed filters have epoxy encapsulants injected into the
cavities either side of the filter elements. The purpose of the
resin is to ‘ruggedise’ the assembly, supporting the pins and
sealing the ceramic to prevent reliability issues from such
as moisture ingress. Poor encapsulants can be susceptible
to cracking away from the metalwork due to temperature
change. This can then allow moisture ingress which can result
in reliability concerns. They can also exert a force on the
ceramic which can result in cracking causing electrical failure.
MIL or Space specifications generally do not demand resin
sealed filters be tested for immersion or accelerated damp
heat testing.
Syfer resin sealed filters use a very high purity, highly filled,
epoxy encapsulant with a very low co-efficient of thermal
expansion – very closely matched to the expansion co-
efficient of the ceramic and other materials used in the
construction. These characteristics enable Syfer filters to be
thermally cycled with very little stress being applied to the
ceramic elements, and with reduced risk of cracking allowing
moisture ingress. Certain Syfer filters have successfully passed
immersion and accelerated damp heat testing.
Screw mount ‘hermetic’ filters generally have glass to metal
seals soldered into place instead of conventional resin seals.
They are better than resin sealed filters in applications
where outgassing is critical, or where the environment is
particularly harsh. MIL or Space specifications generally do
require hermetically sealed filters be tested for immersion
or accelerated damp heat testing. Unless fitted with sealing
rings, they will not normally provide a gas seal between
either side of the mounting bulkhead – the seal is to protect
the internal capacitor elements. Care must be taken when
using the filters, as the exposed solder joints can reflow,
compromising the seal effectiveness, if too high a temperature
is applied to the end terminals.
Solder mount hermetic filters may create a gas seal between
either side of the bulkhead, but this is more dependant on
the sealing capabilities of the solder joint mounting the filter
rather than the filter seal. Usually, solder mount filters only
have a glass seal on one side of the filter body, with the other
end resin sealed. Test plans are normally the same as those
for resin sealed filters. Hermetically sealed solder mount filters
are only normally required in applications where one end of
the filter will be exposed to hash environments, or where
outgassing is critical on one side of the panel.
Panel mount EMI filters - Application considerations
Discoidal capacitor vs tubular capacitor
The original panel mount filters used single layer tubular
capacitors. There is one major advantage of this type of
capacitor - it lends itself to very easy Pi filter construction.
For this reason, Pi filters have tended to be considered the
optimum filter configuration.
As performance demands increased, higher capacitance values
were required. High K, unstable (Z5U / Y5V see page 7)
dielectrics and multilayer tubes began to be used. These use
buried layer electrodes within the tube walls, but the reduced
dielectric thickness resulted in lower voltage withstand
capability. The unstable dielectrics result in poor performance
over the voltage and temperature ranges.
Tubular capacitors have one major flaw - the thin ceramic
walls make them very prone to cracking causing electrical
failures.
As MLCC chip capabilities developed, the discoidal
capacitor appeared in filters. These devices use MLCC chip
technology to produce a very low inductance (low ESL / low
ESR) capacitor giving improved performance and higher
capacitance and voltage ranges (higher capacitance per unit
voltage). They are physically much stronger and robust than
tubes.
Most Syfer panel mount filters use discoidal capacitors for
optimum mechanical strength and high quality X7R or C0G/
NP0 dielectric materials for optimum electrical performance.
However, there are other dielectric materials used in the
manufacture of filters.
Tubular capacitor
Multilayer discoidal capacitor
Tube
based
filters
Disc
based
filters
Vc characteristics possible.
C, L-C, & T circuits easy.
Tight tolerance possible.
Very high capacitance
Advantages
High capacitance.
Pi filters possible.
Suited to Pi filter
manufacture.
Robust.
Cheap.
Seal
Seal
Typical construction of a Pi filter
using tubular capacitors.
Typical construction of a Pi filter
using multilayer discoidal capacitors.
capacitance but low voltage.
not robust – easily cracked
Low capacitance Pi filters,
multilayer tubes = higher
Disadvantages
Low capacitance only,
relatively expensive.
Seal
Seal
Surface mount and panel mount solder-in filters
Solder pad layouts are included with the detailed information for each part.
Recommended soldering profile
Soldering of filters
The soldering process should be controlled such that the filter
does not experience any thermal shocks which may induce
thermal cracks in the ceramic dielectric.
The pre-heat temperature rise of the filter should be kept to
around 2°C per second. In practice successful temperature
rises tend to be in the region of 1.5°C to 4°C per second
dependent upon substrate and components.
The introduction of a soak after pre-heat can be useful as it
allows temperature uniformity to be established across the
substrate thus preventing substrate warping. The magnitude
or direction of any warping may change on cooling imposing
damaging stresses upon the filter.
E01, E03, E07 SBSP ranges are compatible with all standard
solder types including lead-free, maximum temperature
Termination types available surface mount filters
F: Silver Palladium
J: Silver base with nickel barrier (100% matte tin
plating)
A: Silver base with nickel barrier (tin/lead plating
with min 10% lead)
Y: FlexiCap™ with nickel barrier (100% matte tin
plating)
H: FlexiCap™ with nickel barrier (tin/lead plating
with min 10% lead)
m
See text for
maximum
temperature
See page 14 for termination type.
Gradual warm-up to reflow
Do not thermal shock
Termination
Pre-heat
Reflow
Natural cool down
Do not force cool
Cool
E01
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Time
E03
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260°C. For SBSG, SBSM and SFSS ranges, solder time should
be minimised, and the temperature controlled to a maximum
of 220°C. For SFSR, SFST and SFSU ranges the maximum
temperature is 250°C.
Cooling to ambient temperature should be allowed to occur
naturally. Natural cooling allows a gradual relaxation of
thermal mismatch stresses in the solder joints. Draughts
should be avoided. Forced air cooling can induce thermal
breakage, and cleaning with cold fluids immediately after a
soldering process may result in cracked filters.
Note: The use of FlexiCap™ terminations is strongly
recommended to reduce the risk of mechanical cracking.
Soldering to axial wire leads
Soldering temperature
The tip temperature of the iron should not exceed 300°C.
Dwell time
Dwell time should be 3-5 seconds maximum to minimise the
risk of cracking the capacitor due to thermal shock.
Heat sink
Where possible, a heat sink should be used between the
solder joint and the body, especially if longer dwell times are
required.
Bending or cropping of wire leads
Bending or cropping of the filter terminations should not be
carried out within 4mm (0.157”) of the epoxy encapsulation,
the wire should be supported when cropping.
A more comprehensive application note covering
installation of all Syfer products is available on the
Syfer website.
E07
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Installation of filters
SBSP
FILTERSINSTALLATION.ver1
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SBSG
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SBSM
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