FlexiCap™ Overview
FLEXICAP™ BENEFITS
FLEXICAP™ TERMINATION
With traditional termination materials and assembly, the
MLCCs are widely used in electronic circuit design for a multitude of
applications. Their small package size, technical performance and suitability
for automated assembly make them the component of choice for the
specifier. However, despite the technical benefits, ceramic components
are brittle and need careful handling on the production floor. In some
circumstances they may be prone to mechanical stress damage if not used in
an appropriate manner. Board flexing, depanelization, 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
significant board flexing 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 finds out — when equipment fails!
chain of materials from bare PCB to soldered termination
provides no flexibility. In circumstances where excessive stress
is applied, the weakest link fails. This means the ceramic itself may
fail or short circuit. The benefit 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. FlexiCap™
may be soldered using your traditional wave or reflow solder techniques,
including lead free, and needs no adjustment to equipment or current
processes. Knowles has delivered millions of FlexiCap™ components
and during that time has collected substantial test and reliability data,
working in partnership with customers worldwide to eliminate mechanical
cracking. An additional benefit of FlexiCap™ is that MLCCs can withstand
temperature cycling -55ºC to +125ºC in excess of 1,000 times without
cracking. FlexiCap™ termination has no adverse effect on any electrical
parameters, nor affects the operation of the MLCC in any way.
KNOWLES HAS THE SOLUTION — FLEXICAP™
FlexiCap™ 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
flexible epoxy polymer termination material that is applied to the device under
the usual nickel barrier finish. FlexiCap™ will accommodate a greater degree of
board bending than conventional capacitors.
Picture taken at
1,000x magnification
using an SEM to
demonstrate the fibrous
nature of the FlexiCap
TM
termination that absorbs
increased levels of
mechanical stress.
KNOWLES FLEXICAP™ TERMINATION
Ranges are available with FlexiCap™ termination material offering increased
reliability and superior mechanical performance (board flex and temperature
cycling) when compared with standard termination materials. Refer to Knowles
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.
AVAILABLE ON THE FOLLOWING RANGES:
● All High Reliability Ranges
● Standard and High Voltage
Capacitors
● Non-Magnetic Capacitors
● 3-Terminal EMI Chips
● X2Y Integrated Passive
Components
● Open Mode and Tandem
Capacitors
● X8R High Temperature
● Safety Certified Capacitors
Capacitors
SUMMARY OF PCB BEND TEST RESULTS
The bend tests conducted on X7R (2R1) have proven that the FlexiCap™
termination withstands a greater level of mechanical stress before
mechanical cracking occurs. The AEC-Q200 test for X7R (2R1) requires a
bend level of 2mm minimum and a cap change of less than 10ꢀ. Knowles
test to a minimum bend of 5mm for X7R with FlexiCap termination, and
for COG with either FlexiCap or standard termination.
Product X7R (2R1)
Standard termination
FlexiCap™
Typical bend performance under AEC-Q200 test conditions
2mm to 3mm
Typically 8mm to 10mm
APPLICATION NOTES
FlexiCap™ may be handled, stored and transported in the same manner as standard terminated capacitors. The requirements
for mounting and soldering FlexiCap™ 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 FlexiCap™.
Based upon board bend tests in accordance with IEC 60384-1, the amount of board bending required to mechanically crack a FlexiCap™ terminated capacitor
is significantly increased compared with standard terminated capacitors. It must be stressed, however, that capacitor users must not assume that the use of
FlexiCap™ terminated capacitors will totally eliminate mechanical cracking. Good process controls are still required for this objective to be achieved.
7
KNOWLES [ KNOWLES ELECTRONICS ]
