Surface mount capacitors1.4
1.4 - FlexiCap™ termination
MLCCs are widely used in electronic circuit design for a
multitude of applications. Their small package size, technical
performance and suitability for automated assembly makes
them the component of choice for the specier.
However, despite the technical benets, ceramic components
are brittle and need careful handling on the production oor.
In some circumstances they may be prone to mechanical
stress damage if not used in an appropriate manner. Board
exing, depanelisation, mounting through hole components,
poor storage and automatic testing may all result in cracking.
Careful process control is important at all stages of circuit
board assembly and transportation - from component
placement to test and packaging. Any signicant board exing
may result in stress fractures in ceramic devices that may
not always be evident during the board assembly process.
Sometimes it may be the end customer who nds out - when
equipment fails!
Syfer has the solution - FlexiCap™
FlexiCapTM has been developed as a result of listening to
customers’ experiences of stress damage to MLCCs from
many manufacturers, often caused by variations in production
processes.
Our answer is a proprietary exible epoxy polymer termination
material, that is applied to the device under the usual nickel
barrier nish. FlexiCapTM will accommodate a greater degree
of board bending than conventional capacitors.
Syfer FlexiCap™ termination
All ranges are available with FlexiCap™ termination material
offering increased reliability and superior mechanical
performance (board ex and temperature cycling) when
compared with standard termination materials. Refer to Syfer
application note reference AN0001. FlexiCap™ capacitors
enable the board to be bent almost twice as much before
mechanical cracking occurs. Refer to application note AN0002.
FlexiCap™ is also suitable for Space applications having
passed thermal vacuum outgassing tests. Refer to Syfer
application note reference AN0026.
Fired ceramic
dielectric
FlexiCap
TM
termination
base
Intermediate
nickel layer
Tin outer
layer
Metal
electrodes
FlexiCap
TM
MLCC cross section
Application notes
FlexiCapTM may be handled, stored and transported in
the same manner as standard terminated capacitors. The
requirements for mounting and soldering FlexiCapTM are the
same as for standard SMD capacitors.
For customers currently using standard terminated capacitors
there should be no requirement to change the assembly
process when converting to FlexiCapTM.
Based upon board bend tests in accordance with IEC 60384-1
the amount of board bending required to mechanically crack
a FlexiCapTM terminated capacitor is signicantly increased
compared with standard terminated capacitors.
It must be stressed however, that capacitor users must not
assume that the use of FlexiCapTM terminated capacitors will
totally eliminate mechanical cracking. Good process controls
are still required for this objective to be achieved.
● Picture taken at
1,000x magnification
using a SEM
to demonstrate the
fibrous nature of the
FlexiCapTM termination
that absorbs increased
levels of mechanical
stress.
Available on the following ranges:
● All High Reliability ranges
● Standard and High Voltage chips
● Surge Protection and Safety capacitor chips
● 3 terminal EMI chips
● X2Y Integrated Passive Components
● X8R High Temperature capacitors
Summary of PCB bend test results
The bend tests conducted on X7R have proven that
the FlexiCapTM termination withstands a greater level of
mechanical stress before mechanical cracking occurs.
The AEC-Q200 test for X7R requires a bend level of 2mm
minimum and a cap change of less than 10%.
Product
X7R
Typical bend performance under
AEC-Q200 test conditions
Standard termination 2mm to 3mm
FlexiCap™ Typically 8mm to 10mm
FlexiCap™ benets
With traditional termination materials and assembly, the chain
of materials from bare PCB to soldered termination, provides
no exibility. In circumstances where excessive stress is
applied - the weakest link fails. This means the ceramic itself,
which may fail short circuit.
The benet to the user is to facilitate a wider process window
- giving a greater safety margin and substantially reducing the
typical root causes of mechanical stress cracking.
FlexiCapTM may be soldered using your traditional wave
or reow solder techniques and needs no adjustment to
equipment or current processes.
Syfer has delivered millions of FlexiCapTM components and
during that time has collected substantial test and reliability
data, working in partnership with customers world wide, to
eliminate mechanical cracking.
An additional benet of FlexiCap™ is that MLCCs can
withstand temperature cycling -55ºC to 125ºC in excess of
1,000 times without cracking.