What you should know about Ceramic Capacitors ?
▲ 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.
> See our capacitors in catalog
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.
6. 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.
9. Environment
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
SMD CAPACITORS
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).
LEADED COMPONENTS
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.
Manufacturing steps
> See our capacitors in catalog
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.
> See our capacitors in catalog
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.
LEAD STYLES
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.
14. Packaging
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:
Model.
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.
> See our capacitors in catalog
The Felsic HV family of aluminum electrolytic screw terminal capacitors provides great performances in energy density and ultra-long lifetime. For example products can withstand 8 000 hours at 105°C under high values of current which makes them the perfect choice to overcome railway constraints. The family also has one of the lowest ESR for aluminum capacitors, less than 10m0hms in most cases. Products are available for voltages from 160 to 450 Vdc, and offer capacitance values from 1500μF up to 47 000μF. Thus the family is a good compromise between reliability and compacity, with for example 47 000μF @ 160V in a 90x200mm volume.
Designed and qualified for aerospace, the TCM series is available in a through-hole package for horizontal and vertical mounting. TCM common-mode chokes are offered with inductances from 0.7 to 47mH under rated currents from 0.3A to 4A, and thoroughly tested by a dielectric withstanding strength at 1500VAC. Their excellent thermal properties allow the TCMs to operate without a hitch from -55°C up to +125°C, which, combined to the high mechanical resistance of the chosen materials (all meeting to UL94 V0 rating) make those products the perfect fit for aviation, defense and transportation industries.
New range of high voltage ceramic capacitors based on brand new dielectric material C48X, combining most advantages of NPO and X7R dielectrics. Compared to X7R material, C48X dielectric allows to get the same capacitance values under working voltage with the unrivaled advantage of a very low dissipation factor (less than 5.10-4). Besides, it can also withstand very high dV/dt, up to 10kV/μs, which makes it the solution of choice for pulse and fast charge/discharge applications or firing units. Thus capacitors with C48X dielectric appear to be ideally suited for power applications where heat dissipation may be detrimental to performances and reliability.
The new NHB series is a complete range of MLCC based on NPO dielectric material providing a very high Self Resonant Frequency and limiting the parasite Parallel Resonant Frequencies. The series is available in 1111 size with capacitance ranging from 0.3pF to 100pF. NHB series offers excellent performance for RF power applications at high temperature up to 175°C and at 500 VDC. The lowest ESR is obtained by combining highly conductive metal electrodes and proprietary of new NPO low loss rugged dielectrics. NHB series particularly fits for high power and high frequency applications such as: cellular base station equipment, broadband wireless service, point to point / multipoint radios and broadcasting equipment.