What you should know about Ceramic Capacitors ?
Discover the basic information about ceramic capacitors, to improve your choice
▲ What you should know about Ceramic Capacitors ?
1. Materials expert
For 50 years and as a market leader, EXXELIA’s comprehensive knowledge of the materials properties and performances have enabled us to design capacitors in Porcelain, NPO, BX, 2C1, BP, X7R and –2200ppm/°C ceramics.
2. Custom Designs
Our catalog products don’t meet your application?
Based on the valuable experience accumulated over the design of 2,000+ specific ceramic capacitors, you can trust EXXELIA to define a qualitative custom solution in a time effective manner.
3. No Obsolescence
Choosing a standard or custom EXXELIA product means you won’t have to worry about obsolescence.
4. Typical Applications
- Aerospace & Defense: cockpit panels, flight control, radio systems, missile
- guidance systems…
- Space: military and commercial satellites, launcher…
- Medical: MRI, external defibrillators, implantable devices…
- Telecommunications: base stations…
- Oil and gas: drilling tools, MWD, LWD, wellheads…
5. ISO 9001 And AS9100C
Quality is at the core of Exxelia’s corporate culture. Each sites has its own certifications.
Capacitors manufactured by EXXELIA comply with American and European standards and meet the requirements of many international standards.
For Space qualified parts (ESA QPL), please refer to our catalog «Ceramic capacitors for Space applications».
7. Quality & Reliability
EXXELIA is committed to design and manufacture high quality and reliability products. The test cycles reproducing the most adverse operating conditions over extended periods (up to 10 000 hours) have logged to date well over 5.109 hours/°Component.
Failure rate data can be provided upon request.
8. Conflict minerals
EXXELIA is committed to an approach based on «Conflict Minerals Compliance». This US SEC rule demands complete traceability and a control mechanism for the mineral procurement chain, encouraging importers to buy only «certified» ore.
We have discontinued relations with suppliers that procure from the Democratic Republic of the Congo or an adjoining country.
EXXELIA is committed to applying a robust environmental policy, from product design through to shipment. To control its environmental footprint and reconcile this with the company’ functional imperatives, our environmental policy provides for the reduction or elimination of hazardous substances. We also focus on compliance with European Union directives and regulations, notably REACH and RoHS.
10. RoHS Compliancy
The capacitor terminations are generally protected by a nickel barrier formed by electrolytic deposit. This barrier gives chip capacitors leaching performance far exceeding the requirements of all applicable standards. The nickel barrier guarantees a minimum resistance to soldering heat for a period of 1 minute at 260°C in a tin-lead (60/40) or tin-lead-silver (62/36/2) bath without noticeable alteration to the solderability. It also allows repeated soldering-unsoldering and the longer soldering times required by reflow techniques.
However nickel barrier amplifies thermal shock and is not recommended for chip sizes equal or greater than CNC Y (30 30) - (C 282 to C 288 - CNC 80 to CNC 94).
As well as for SMD products, leaded capacitors ranges can also be RoHS. These products, which are characterized by the suffix «W» added to the commercial type, are naturally compatible with the soldering alloys used in RoHS mounting technology. The connections coating is generally an alloy SnAg (with a maximum of 4% Ag). However, on a few products that EXXELIA will precise on request, the coating is pure silver.
11. MLCC Structure
12. Equivalent circuit
Capacitor is a complex component combining resistive, inductive and capacitive phenomena. A simplified schematic for the equivalent circuit is:
13. Dielectric characteristics
Insulation Resistance (IR) is the resistance measured under DC voltage across the terminals of the capacitor and consists principally of the parallel resistance shown in the equivalent circuit. As capacitance values and hence the area of dielectric increases, the IR decreases and hence the product (C x IR) is often specified in Ω.F or MΩ.µF.
The Equivalent Series Resistance (ESR) is the sum of the resistive terms which generate heating when capacitor is used under AC voltage at a given frequency (f).
Dissipation factor (DF) is the ration of the apparent power input will turn to heat in the capacitor:
DF = 2π f C ESR
When a capacitor works under AC voltage, heat power loss (P), expressed in Watt, is equal to:
P = 2π f C Vrms2 DF
The series inductance (Ls) is due to the currents running through the electrodes. It can distort the operation of the capacitor at high frequency where the impedance (Z) is given as:
Z = Rs + j (Ls.q - 1⁄(C.q)) with q = 2πf
When frequency rises, the capacitive component of capacitors is gradually canceled up to the resonance frequency, where :
Z = Rs and LsC.q2 = 1
Above this frequency the capacitor behaves like an inductor.
SMD environmental tests
Ceramic chip capacitors for SMD are designed to meet test requirements of CECC 32100 and NF C 93133 standards as specified below in compliance with NF C 20700 and IEC 68 standards:
- Solderability: NF C 20758, 260°C, bath 62/36/2.
- Adherence: 5N force.
- Vibration fatigue test: NF C 20706, 20 g, 10 Hz to 2,000 Hz, 12 cycles of 20 minutes each.
- Rapid temperature change: NF C 20714, –55°C to + 125°C, 5 cycles.
- Combined climatic test: IEC 68-2-38.
- Damp heat: NF C 20703, 93 %, H.R., 40°C.
- Endurance test: 1,000 hours, 1.5 URC, 125°C.
STORAGE OF CHIP CAPACITORS
TINNED OR NON TINNED CHIP CAPACITORS
Storage must be in a dry environment at a temperature of 20°C with a relative humidity below 50 %, or preferably in a packaging enclosing a desiccant.
STORAGE IN INDUSTRIAL ENVIRONMENT:
- 2 years for tin dipped chip capacitors,
- 18 months for tin electroplated chip capacitors,
- 2 years for non tinned chip capacitors,
- 3 years for gold plated chip capacitors.
STORAGE IN CONTROLLED NEUTRAL NITROGEN ENVIRONMENT:
- 4 years for tin dipped or electroplated chip capacitors,
- 4 years for non tinned chip capacitors,
- 5 years for gold plated chip capacitors.
Storage duration should be considered from delivery date and not from batch manufacture date. The tests carried out at final acceptance stage (solderability, susceptibility to solder heat) enable to assess the compatibility to surface mounting of the chips.
SOLDERING ADVICES FOR REFLOW SOLDERING
Large chips above size 2225 are not recommended to be mounted on epoxy board due to thermal expansion coefficient mismatch between ceramic capacitor and epoxy. Where larger sizes are required, it is recommended to use components with ribbon or other adapted leads so as to absorb thermo-mechanical strains.
RECOMMENDED FOOTPRINT FOR SMD CAPACITORS
Ceramic is by nature a material which is sensitive both thermally and mechanically. Stresses caused by the physical and thermal properties of the capacitors, substrates and solders are attenuated by the leads.
Wave soldering is unsuitable for sizes larger than 2220 and for the higher ends of capacitance ranges due to possible thermal shock (capacitance values given upon request).
Infrared and vapor phase reflow, are preferred for high reliability applications as inherent thermo-mechanical strains are lower than those inherent to wave soldering.
SOLDERING ADVICES FOR IRON SOLDERING
Attachment with a soldering iron is discouraged due to ceramic brittleness and the process control limitations. In the event that a soldering iron must be used, the following precautions should be observed:
- Use a substrate with chip footprints big enough to allow putting side by side one end of the capacitor and the iron tip without any contact between this tip and the component,
- place the capacitor on this footprint,
- heat the substrate until the capacitor’s temperature reaches 150°C minimum (preheating step, maximum 1°C per second),
- place the hot iron tip (a flat tip is preferred) on the footprint without,
- touching the capacitor. Use a regulated iron with a 30 watts maximum,
- power. The recommended temperature of the iron is 270 ±10°C. The temperature gap between the capacitor and the iron tip must not exceed 120°C,
- leave the tip on the footprint for a few seconds in order to increase locally the footprint’s temperature,
- use a cored wire solder and put it down on the iron tip. In a preferred way use Sn/Pb/Ag 62/36/2 alloy,
- wait until the solder fillet is formed on the capacitor’s termination,
- take away iron and wire solder,
- wait a few minutes so that the substrate and capacitor come back down to the preheating temperature,
- solder the second termination using the same procedure as the first,
- let the soldered component cool down slowly to avoid any thermal shock.
TAPE AND REEL
The films used on the reels correspond to standard IEC 60286-3. Films are delivered on reels in compliance with document IEC 286-3 dated 1991.
Minimum quantity is 250 chips.
Maximum quantities per reel are as follows:
- Super 8 reel - Ø 180: 2,500 chips.
- Super 8 reel - Ø 330: 10,000 chips.
- Super 12 reel - Ø 180: 1,000 chips.
Reel marking complies with CECC 32100 standard:
- Rated capacitance.
- Capacitance tolerance.
- Rated voltage.
- Batch number.
15. Dimensional characteristics of chips tray packages
16. High Q Capacitors Tape and Reel Packaging Specifications
17. EIA standard capacitance values
Following EIA standard, the values and multiples that are indicated in the chart below can be ordered. E48, E96 series and intermediary values are available upon request.
18. EIA capacitance code
The capacitance is expressed in three digit codes and in units of pico Farads (pF).
The first and second digits are significant figures of the capacitance value and the third digit identifies the multiplier.
For capacitance value < 10pF, R designates a decimal point.
See examples below:
19. Part marking voltage codes
Use the following voltage code chart for part markings:
20. Part marking Tolerance codes
Use the following tolerance code chart for part markings:
21. Reliability levels
Exxelia proposes different reliability levels for the ceramic capacitors for both NPO and X7R ceramics.
As the world’s leading manufacturer of specific passive components, we stand apart through our ability to quickly evaluate the application specific engineering challenges and provide a cost-effective and efficient solutions.
For requirements that cannot be met by catalog products, we offer leading edge solutions in custom configuration: custom geometries, packaging, characteristics, all is possible thanks to our extensive experience and robust development process, while maintaining the highest level of reliability.
Where necessary, special testing is done to verify requirements, such as low dielectric absorption, ultra-high insulation resistance, low dissipation factor, stability under temperature cycling or under specified environmental conditions, etc.
Magnetic Components based on Adaptive CCM Technology at APEC – Booth# 653 –
Exxelia will exhibit the CCM series during the Applied Power Electronics Conference at Exxelia’s booth #623 from March 27-30, 2017 in Tampa, FL. Exxelia designed CCM technology to respond to the growing interest of electronic engineers for inductors and transformers with multiple outputs, high power density and reduced footprint. Qualified for aeronautic and space applications, the CCM product line features terrific robustness. The monolithic design provides high mechanical performance, proven by the successfully testing in accordance with MIL-STD-202 (methods 213 and 204). The series offers five different sizes, allowing optimized component design in a pick-and-place surface mount (SMD) package. Through-hole (TH) packages are also available upon request. The CCM series is particularly flexible with a number of pins options available, from 2×6 pins for the smallest package, up to 2×10. CCM transformers and inductors can operate over a wide temperature range with a minimal temperature of -55° C. The standard thermal grade of the technology is 140° C. Thanks to the technology design, the thermal resistance is 30% lower than standard industrial components. The epoxy molding protecting the winding ensures a lower temperature gradient and a better heat dissipation. Each unit is thoroughly tested with a dielectric withstanding strength of 1,500 VAC. Component materials meet UL 94-V0 rating. Exxelia can evaluate losses and related temperature rise thanks to an in-depth knowledge of CCM technology. Thermal resistance data is available for each package size. Exxelia can also manufacture products in CCM technology according to MIL-STD-981.
New Plug&Play filters for datacenters and mission critical facilities
Electronic equipment can leak sensitive information over conducted or radiated electromagnetic emanations, and signals transmitted down unprotected lines can potentially be intercepted. That’s why filters are implemented into systems to prevent EMI disturbances, as TEMPEST filters stop the high frequency EM signals (or noise) emanating inside the secured environment. Exxelia has a long history of manufacturing state-of-the-art electromagnetic interference (EMI) filtering technologies for space, avionic and defense markets. Thanks to this in-depth knowledge, Exxelia came to the conclusion that the installation of a product is as critical as its reliability, especially when shielding continuity and sensitive copper terminals are involved. That’s where Exxelia’s new full range of TEMPEST pluggable filters will save time and spare headaches! The 9260W series is a multi-socket line extension with a built-in 16A Tempest filter (minimum 60dB, from 100KHz to 1GHz), CE qualified according to EM 60950-1 standard. 9260W series Plug&Play solution is available with UK, US and EU standard plugs and can be provided with any other standard plug upon request. In addition, Exxelia completed its offer with the 9259W series of pluggable filters featuring various plug interfaces such as VGA/DVI, USB, Ethernet, Phone, Audio and much more. 9260W series and 9259W series are both fully compliant with EMC expectations and allow considerable time saving and cost-effectiveness. When a standard filter needs to be wired and shielded to each socket one-by-one before carefully re-closing the whole equipment, Exxelia new series can be installed using no special tools and with a smaller footprint. To all people handling sensitive information, a simple plugging operation is now enough to protect their data. Available now, 9259W and 9260W series are fully customizable upon request.