ITW Paktron

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ITW Paktron 1205 McConville Road, Lynchburg
Virginia 24502 USA TEL [phone] FAX
434-239-4730 EMAIL itwpaktron_at_paktron.com
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Seminar Outline

• Comparison of MLP vs MLC Capacitor Robustness
• MLP Attributes
• Typical Circuit Applications
• Performance/Reliability

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Family Tree of Capacitors
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Ceramic Capacitor Cross-Section
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MLP Internal Structure
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MLC Cracking
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CTEs
On Typical Components and Substrates
CTE Coefficient of Thermal Expansion a.k.a. TEC
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MLC Capacitors
Palladium Replacement
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Ceramic Capacitor withBase Metal Electrode
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Ceramic CapacitorShort Circuit Failure
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Convection Reflow Profile (Typical)
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IR Reflow Profile (Typical)
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Board Flexure Comparison between Surface Mount
Multi-layer Ceramic and Film Capacitors

EIA JRC3402 Board Flexure
1.0mm Deflection
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Results of MLC Board Flexure
4.0mm Deflection
Typical 4.0mm Deflection 1812 Failure
Typical 16.0mm Deflection 2225 Failure
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MLP Board Flexure Robustness
1812 MLP Termination after 7.0mm Deflection
Post Board Flexure
A New 1812 MLP Termination
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Real World Design Considerations to Avoid
Capacitor Cracking

• Avoid FR-4 boards or eliminate PCB flexure
• Use only tiny MLCs (smaller than 1812, and less
  than 0.1mfd)
• Employ lead frame terminations vs bare chip
• Burn-in,vibrate and sonically screen 100
• Avoid temperature extremes ramp-up, thermal
  shock etc.
• DESIGN WITH ROBUST MLP CAPACITORS

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Paktrons Interleaf Technology
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MLP Capacitors
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MLP Pulse Testing (dv/dt)
A type of test that shows both the reliability
and performance capability of MLP capacitors is
dv/dt (pulse) testing. This type of test
stresses the metal interconnections of the
capacitor. Typically, this type of test is done
at room temperature. The test results show no
adverse effects after the parts have been
subjected to almost 37,000 pulses.
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Metallized Film Construction
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Wound vs. Stacked Comparison
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MLP Asynchronous Dynamics Testing
A standard test used by power converter
manufacturers to establish robustness is through
the use of asynchronous dynamics. The unit
under test is connected to a DC source at 75vdc
through a mercury wet relay to avoid contact
bounce. The output of the converter is connected
to an 8A load and to a short circuit relay. The
converter is then placed in an oven at 85C at
85 RH for twenty-four hours. The relays are
switched asynchronously at time intervals of 11
seconds and seventeen seconds respectively.
Under this scenario, seven thousand, five hundred
cycles can be completed in the twenty-four
hours. This type of 24 hour test is very
severe and translates to twenty years of life
with daily turn on and short circuit fault
condition. Following this type of testing it is
typical for the capacitance value of a MLP
capacitor to drop by no more than 0.01 with no
failures occurring.
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Capacitor Fusing
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MLP Clearing
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Capacitance Change vs. DC Bias
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Dissipation Factor vs. Vrms
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ESR vs. Temperature
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ESR vs. Frequency
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Typical Applications

Automotive
Computer
Consumer
Telecommunications
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Differential vs. Common Mode Noise
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Typical EMI Filters
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24/48 Level B Single Output Filter
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24 LevelA Triple Output Filter
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24LevelBTripleOutputFilter
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Filter Module Schematic
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Filter Application
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Low Pass Filter
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High Voltage Input Filter
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AC and Quasi AC Input Filter
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Resonant Tank Circuit
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Output Filter
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Reliability
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Capacitor Level Testing
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Failure Rate per 1000 Hours
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FIT Rate vs. RVDC
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Failure Rate per 1000 Pieces
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Failure Rate per 1000 Pieces
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Capstick MLP Capacitor
Advantages over Ceramics
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Capstick vs. the Competition
No matter how you figure it, the Paktron part is
just a better fit for your application!