Multilayer Polymer Film Capacitors Key Components in Differential EMI and RFI Bypass Applications Where Short Circuit and Heat Runaway Failures Cannot be Tolerated APEC 2003 Exhibitor Seminar February 11, 2003 ITW Paktron 1205 McConville Road, Lynchburg Virginia 24502 USA TEL: 434-239-6941 · FAX: 434-239-4730 EMAIL: email@example.com
Seminar Outline • Comparison of MLP vs MLC Capacitor “Robustness” • MLP Attributes • Typical Circuit Applications • Performance/Reliability
CTE’s On Typical Components and Substrates CTE – Coefficient of Thermal Expansion a.k.a. TEC
MLC Capacitors Palladium Replacement
Ram with 14cm radius, Travels at 20mm/min. Capacitance Bridge 90 mm Board with Leads Attached Board Support Board Flexure Comparison between Surface Mount Multi-layer Ceramic and Film Capacitors EIA JRC3402 Board Flexure 1.0mm Deflection
Results of MLC “Board Flexure” 4.0mm Deflection Typical 4.0mm Deflection 1812 Failure Typical 16.0mm Deflection 2225 Failure
MLP “Board Flexure” Robustness 1812 MLP Termination after 7.0mm Deflection “Post Board Flexure” A New 1812 MLP Termination
“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
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.
DC Source @ 75VDC DC-DC Converter Load @ 8A Async Relay Box 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 85°C 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.
Typical Applications Automotive Computer Consumer Telecommunications
Capstick MLP Capacitor Advantages over Ceramics
Paktron Competition Capstick® vs. the Competition No matter how you figure it, the Paktron part is just a better fit for your application!