CalRamic Capacitor Education Series: Mechanical Configurations AN109-3

CAPACITOR BASICS III – Mechanical Configurations

In our continuing educational series on ceramic capacitors, we are sharing the Application Note 109-3, Capacitor Basics 3 - Single-layer versus Multilayer designs.   

In their simplest form ceramic capacitors are comprised of a single sheet or layer of dielectric with electrodes printed on each side. This approach may be ideal for higher voltage, lower capacitance designs, but may not be considered practical for applications where a significant amount of capacitance is required.  Material and process constraints place finite limitations on the overall maximum size of a plate and the minimum thickness that one can reliably cast dielectric. Once those limitations have been reached the engineer is forced to look at alternative methods by which these challenges can be managed and multilayer capacitor designs provide that option.

 
We offer many different configurations for High Voltage Ceramic Capacitors. Give us a call to discuss your application and the best capacitor solution for your project.

CalRamic Ceramic Capacitor Application Note Series: AN101

SOLDERING HIGH VOLTAGE MULTILAYER CERAMIC CAPACITORS

Multilayer Ceramic Capacitors (MLCC’s) are complex composite mechanical structures composed of alternating layers of a dense ceramic substrate and metal electrodes, which are connected by a metal termination that typically contains a glass frit. Each of these materials is characterized by a different Coefficient of Thermal Expansion (CTE), which makes the completed structure highly susceptible to thermal shock.

The degree to which a ceramic capacitor may potentially be effected by thermal shock can be influenced by several factors including the overall mass, size, and geometry of the device itself, the number, thickness and density of it’s ceramic layers and metal electrodes, the type of termination material utilized and the integrity with which these materials effectively form a single monolythic structure. In addition, there are several external influences that can also impact the degree to which a capacitor may be subjected to thermal stress including, but not limited to, the range of temperatures encountered, the means by which the part is exposed and time of exposure, the type of substrate to which the capacitor is being mounted, and the thermal characteristics and proximity of other components within the assembly.

While thermal shock conditions exist, the possibility of introducing substantial stress within the structure is significantly increased and unless preventative measures are introduced that mitigate these conditions, formation of micro fractures within the capacitor body are highly likely. These micro fractures, depending on their severity, may or may not be detectable thru common testing and inspection practices. This poses significant concern inasmuch as the suspect part may represent a latent failure whereby the product initially presents itself as an acceptable unit and may continue to operate until such time as moisture penetrates the flaw site, and / or it is subjected to further
mechanical of thermal stress. In addition, the actual failure may be delayed for an extended period of time and may not be detected until the finished product has been placed in the field.

MLCC Soldering at CalRamic Technologies LLC

One area where the initiation of thermal shock can be addressed is in the soldering processes utilized for mounting ceramic capacitors. Ensuring adequate pre-heat and post heat conditions and the selection of the most appropriate soldering process can be critical to the success of the operation. This Application Note outlines some of the more common soldering processes utilized for mounting larger MLCC chip capacitors, including Infrared / Convection Reflow soldering, Vapor Phase Reflow soldering and Hand soldering. These recommendations if applied properly and tailored to the specific application, should minimize the risk for thermal shock and subsequent micro fracturing of these style capacitors.

The complete AN101 can be read and referenced on this page: http://calramic.com/Design/Assets/PDF_files/AN101.pdf

CalRamic HV Ceramic Capacitor Educational Series 109-5

Performance Characteristics

The following Application Note defines the various characteristics that affect performance of the capacitor. Information provided here will give the reader an appreciation for how a capacitor may behave when operated within their intended operating environment. Topics covered include:

• Capacitor Equivalent Circuit page 1
• Equivalent Series Resistance page 2
• Dissipation Factor page 2
• Quality Factor page 3
• Equivalent Series Inductance page 3
• Impedance page 3
• Insulation Resistance page 5
• Working Voltage page 7
• Dielectric Strength page 8
• Aging page 8
• Temperature Coefficient page 9
• Voltage Coefficient page 11
• Voltage – Temperature Coefficient page 12
• Dielectric Absorption page 13
• Piezoelectric materials / Electro-Mechanical Coupling page 13

The complete application note can be read at: http://calramic.com/Design/Assets/PDF_files/AN109-5.pdf

The entire series can be viewed on our web site at www.calramic.com.
 

CalRamic Attends its 9th APEC Conference

Last week Jeff Day, CalRamic CEO, attended the 30th Anniversary APEC conference in Charlottle, North Carolina.  It was Jeff's 9th year attending the conference, which he considers the best audience and show for the Power Electronics Industry using High Voltage Ceramic Capacitors.  Attendees represent a broad industry spectrum, which included Downhole analytical equipment, High temperature Aircraft electronics, Military and Space Electronics, and University research.

Jeff Day, CalRamic Technologies LLC CEO, discusses HV ceramic capacitor application with APEC attendee.

We were also visited by a number of University Academia working on DC-DC type convertors.  Our mission is to supply all National and International Universities with Capacitor samples for their studies free of charge.  Students always remember the companies that help provide lab equipment and supplies, which has been Jeff's case since his days as a University of Washington student.

CalRamic APEC 2015 booth.

Thank you to the attendees that visited our booth.  We look forward to next year's conference in Long Beach.

HV Ceramic Capacitors for X-Ray and Diagnostic Applications

High voltage ceramic capacitors are necessary for high frequency purposes like x-ray and diagnostic applications.  X-Ray processes can range from bomb detection to bone densitometry.  The high voltage ceramic capacitors manufactured by CalRamic provide the required high reliability and superior performance for these applications.

One such diagnostic application example, shown below, is the Gamma Camera.  The device is used to image gamma radiation emitting isotopes that are injected or inhaled into the patient.  Flat crystal planes are coupled into an optical array that counts the gamma photons absorbed by the crystals.  Two-dimensional images are created from the captured gamma radiation.  This imaging technique is used to scan the brain, thyroid, lungs, liver, gallbladder, kidneys and skeleton.  Unlike conventional x-ray techniques that scan structure and anatomy, the gamma camera produces imagery that maps the function and processes of the body.

HV disc low loss capacitors (CRT-0019), along with the HV disc capacitors (CRT-0006) and the HV multilayer capacitors (CRT-0010), manufactured by CalRamic, would provide the capacitance necessary for successful application in the X-Ray/diagnostic industry.  These capacitors are manufactured under strict quality control guidelines to ensure unparalleled performance in high voltage applications.

These and other products can be found on the products page: www.calramic.com/CalRamic-capacitors-products.html.