A

AC Line

AC line applications connect to the main electricity supply used by residential, commercial, and light industrial applications.

AC Film

AC film capacitors are used in filtering, power factor correction, clamping, snubbing, switching, commutation circuits or as motor run capacitors. These applications take advantage of the low dissipation factor, low dielectric absorption and high insulation resistance of the polypropylene film.

AO-CAP

Polymer aluminum capacitors have an aluminum oxide dielectric and a solid polymer cathode. This conductive cathode minimizes ESR which improves capacitance retention at high frequencies. These solid capacitors can be operated without voltage derating.

Axial aluminum electrolytic

Definition: Applications that require stable bulk capacitance in wide-ranging environments benefit from axial aluminum electrolytic capacitors. Features such as all-welded construction, combined with a high-quality lid, gasket and sealing system, ensure rugged performance and help minimize leakage or gas diffusion of the electrolyte.

AC Line Filtering

Definition:

AC line filters use inductors and safety rated (X & Y) capacitors to remove noise. These “safety capacitors” are designed to fail open in the unlikely event they fail.

B

Buck Regulator

Definition:

A buck or step-down regulator is a type of switching regulator. Its output voltage is lower than its input voltage.

Switching regulators use a transistor to efficiently transfer energy between the capacitor and inductor to create the output voltage. When the transistor is in the on-state the inductor will energize, as it is energizing it will produce an opposing voltage across it’s terminals. That voltage is what the capacitor is charged to and when the charged capacitor will release that charge to the load.

In a buck the ratio of input voltage to output voltage is proportional to the duty cycle of the switching frequency.

Boost Regulator

Definition:

A boost or step-up regulator is a type of switching regulator. Its output voltage is higher than its input voltage. Switching regulators use a transistor to efficiently transfer energy between the capacitor and inductor to create the output voltage. When the transistor is in the on-state, an inductor will be energized. The transistor then changes to its off state. In the off state, the transistor will release it’s current onto the capacitor. The capacitor responds to the change in current by producing a high voltage at it’s terminals. It is this voltage that is applied to the load.

The ratio of input voltage to output voltage is proportional to the duty cycle of the switching frequency.

Band-Pass Filter

Definition:

A band-pass filter is an electronic filter that will reject signals below a low frequency and above a high frequency. Signals that fall between the two limits are passed with minimal attenuation.

C

C0G Ceramic 

The Electronics Components, Assemblies & Materials Association (EIA) characterizes C0G dielectric as a Class I material. Components of this classification are temperature compensating. Typically, they are used for resonant circuit applications or those where Q and stability of capacitance characteristics are required. C0G exhibits no change in capacitance with respect to time or voltage while exhibiting a negligible change in capacitance with reference to ambient temperature. Capacitance change is limited to ±30 ppm/ºC from -55°C to +125°C.  

For more information about EIA Classifications, see this FAQ on Temperature Coefficients. C0G capacitors are sometimes called “NPO” or “NP0”. 

This datasheet has more information about KEMET’s C0G Ceramic Capacitors. 

 

Capacitance Equation 

C = Capacitance
ε0= Permittivity of free space
κ = Dielectric constant
A = Electrode area
d = Dielectric thickness 

 

Capacitor Stacks 

Capacitor Stacks are a series of capacitors mounted in stacks of 2, 3, 4 and 6 components into a single compact surface mount package. Capacitor stacks, also commonly referred to as bulk capacitance offers a broad range of capacitance and voltage ratings for applications in all market segments. 

 

Category Temperature (Tc) 

Maximum recommended operating temperature; voltage derating may be required at TC. 

 

Category Voltage (Uc) 

Maximum recommended peak DC operating voltage for continuous operation at the category temperature (TC). 

 

Ceramic Array 

Definition: KEMET’s Ceramic Chip Capacitor Array is available with either C0G or X7R dielectric. These arrays are multiple capacitor elements integrated into one common monolithic structure. 

Array technology offers reduced placement costs and increased throughput. This is achieved by alternatively placing one device rather than two or four discrete devices. Use of ceramic arrays also saves board space which translates into increased board density and more functions per board. Ceramic Arrays consume only a portion of the space required for standard chips resulting in savings in inventory and pick/place machine positions. 

More information about KEMET Ceramic Arrays can be found in the C0G Array and X7R Array datasheets. 

 

Clamping Voltage 

Clamping voltage is the highest voltage that a protection device, such as MOV, allows to pass before activating. Once activated, a varistor becomes a low impedance path. This function is useful for limiting transient voltages in a circuit. 

 

Constant Current Regulator 

Constant Current Regulators (CCRs) maintain a constant output current even if operating from a varying voltage. They are ideal for driving LEDs in lighting applications. They are also useful as current sources for shunt references, or for micro-power biasing, as well as buffering and current-limiting applications. 

 

Coupling 

A coupling capacitor is used to remove a DC offset from an AC signal such as an analog music signal. This enables the signal to be transmitted between two circuits that may have different DC bias voltages. 

 

Cracking 

Cracking also known as flex cracks are created in capacitors when board flex stress/bending stress is applied to a circuit board with ceramic components already affixed to the PCB. KEMET offers several board flex crack mitigation products to eliminate these issues. 

Learn more about what Flexible Mitigation Capacitors KEMET offers or read a whitepaper on Flexible Termination Reliability in Harsh Environments. 

 

Creepage 

Creepage is the shortest path between two conductive parts, or between a conductive part and the bonding surface of the equipment, measured along the surface of the insulation. Many factors can define the creepage distance of an HV MLCC…not just the termination separation. Solder overrun can shorten the creepage distance, as well as surface contamination (especially on an X7R dielectric that has a more porous surface) related to the end customer’s processing. Contaminants can become trapped in the pores and allow arcing despite rigorous adherence to published creepage specs. 

Learn more about Arc Shield Technology, read a whitepaper on ArcShield for Automotive, or see what High-Voltage Ceramic Capacitors KEMET offers. 

 

Curie Temperature 

Also known as the Curie point, is the critical point where a material’s intrinsic magnetic moments change direction. Materials have different structure of intrinsic magnetic moments that depend on temperature. The Curie temperature can also be used to describe the temperature where a material’s spontaneous electric polarization changes to induced electric polarization or the reverse upon reduction of the temperature below the Curie temperature. 

 

CV 

The amount of charge stored in a capacitor depends on the capacitance and voltage rating, also known as the CV product. Sometimes we refer to similar terms: “high CV” or “CV Density.” 

D

DC Bias Effect for MLCCs 

When a DC voltage is applied to class-2 and class-3 multilayer ceramic capacitors (MLCCs), like X7R or Y5V, they lose capacitance. For commercial and automotive grade capacitors, manufacturers typically do not specify this coefficient, or loss. 

Military-Grade MLCCs with a twoletter designator like BX will have a specified voltage coefficient. 

KEMET’s KSIM tool can be used to estimate the DC Bias for a KEMET MLCC. 

 

DC Film 

DC film capacitors are especially useful in high voltage applications with excellent ripple current capabilities. In DC link circuits they are alternatives to aluminum electrolytic caps when very long operational life is required. 

 

DC Link 

A DC link circuit is a method to connect two AC systems that have different voltages and frequencies by way of an intermediate DC stage. After power is converted to DC, it is stored in a capacitor while being converted back to AC. The DC link capacitor will generally have a high voltage rating (>400 VDC), low dissipation factor and low inductance. 

 

Decoupling Capacitors 

Decoupling capacitors (also known as bypass capacitors) are used to supply just-in-time energy to circuits during times of elevated load. The reason for this need of additional energy because of the transient response time of voltage regulators. Regulators supply stable voltage at a constant load current, but if that load current suddenly changes there is a finite amount of time that needs to elapse so that the voltage regulator can adjust to the new load. During this transient time, the output voltage of the regulator may exhibit slumps or ringing. In many cases, this is not an issue, but in microprocessor or microcontroller applications this can be an issue. Those devices can exhibit unwanted behavior such as resets during the transient time. A bypass capacitor is implemented to mitigate this issue. The amount of bypass needed depends on the size and duration of the transient. 

 

Derating 

Derating describes the practice of over specifying or over-designing the components of a circuit. When it comes to capacitors, the effective capacitance changes with the applied voltage, frequency, and temperature. Therefore, it becomes necessary to find a capacitor that will still maintain the desired capacitance under those conditions. Different types of capacitors have different derating rules. 

You can use KEMET’s K-SIM tool in order to simulate what the behavior of capacitors looks like under different voltage, temperature, and frequency conditions. 

 

Dielectric 

A dielectric is a non-conductive material used to store charge from an applied electric field. If a large enough field (or voltage) is applied, the dielectric will breakdown causing a short between the capacitor’s electrodes. Examples are aluminum oxide (Al2O3), barium titanate (BaTiO3), polypropylene and tantalum pentoxide (Ta205). 

 

Dielectric Absorption 

Is the effect by which a capacitor has been charged for a long time and the terminals will remain/develop a small voltage even after been completely discharged. 

 

Dielectric Constant 

The ability for a material to hold an electrostatic field is defined as the dielectric constant. Different materials have different dielectric constants. 

 

Differentiator 

A differentiator is a circuit that produces an output voltage proportional to the rate of change of the input voltage. 

 

Dissipation Factor (DF) 

Dissipation factor (DF) is an important parameter for capacitors used in AC systems and describes the ratio of energy dissipated to energy stored. 

E

Electrical Double Layer Capacitor (EDLC) 

A supercapacitor’s proper name is a : Electrical Double-Layer Capacitor or EDLC. More information can be found in the Supercapacitor Glossary Entry. 

 

Electrode 

Electrodes are made of conductive materials that are in contact with the dielectric layer and the external terminals. Terminals provide a connection between the capacitor and the circuit.
In polarized capacitors like aluminum and tantalum, the positive electrode (terminal) is called the anode. The negative electrode (terminal) is called the cathode. 

 

Electrostriction 

Electrostriction is a behavior of all dielectrics in which the material suffers mechanical deformation, or changes in shape, under the application of an electric field. Class II and Class III ceramic dielectric are made using ferroelectric materials that display greater effects of electrostrictive movement. You will recognize these ceramic types as X7R, X5R, Z5U, and Y5V. When the mechanical deformation occurs, the result can be a sound emission such as an audible hum (i.e., “singing”). Several capacitors mounted closely together on the board can amplify the sound to the point that it is noticeable. See also Piezoelectric Effect. 

 

EMI Filters 

EMI filters can either be created using discrete components or provided as customized modules. Discrete filters commonly used in AC-Line applications may include X-Y Capacitors and AC Chokes. A prepackaged filter combines these elements into a ready to install module. 

See Also 

KEMET’s EMI Filter Brochure 

Applications for EMI Filters 

 

ESD 

Electrostatic Discharge (ESD) is defined as the transfer of electricity between two electrically charged objects at different potentials usually caused by contact, an electrical short, or dielectric breakdown. 

For more information regarding ESD and MLCCs, see this 1999 CARTS Paper 

 

Equivalent Series Inductance (ESL) 

Equivalent series inductance (ESL) is a non-ideal property of a capacitor that represents the parasitic inductances associated with the constituent parts, such as leads, electrodes and dielectric. 

See also Impedance (Z). 

 

Equivalent Series Resistance (ESR) 

Equivalent series resistance (ESR) is a non-ideal property of a capacitor. It represents the resistance of the capacitor’s terminals and electrodes. The ESR of a capacitor changes with applied frequency. The different capacitors types all have different ESR properties and care must be taken to ensure that the selected capacitor has an ESR response compatible with the application in which is being used. 

The ESR can also be thought of as the real part of the capacitor’s impedance. The is the ESR that gives rise to the heating of the component when ripple current is applied. 

See also Impedance (Z). 

F

Ferroelectric 

Ferroelectricity is a property of certain materials that have a spontaneous electric polarization that can be reversed by the application of an external electric field. The nonlinear nature of ferroelectric materials is highly used to make capacitors with tunable capacitance. Paraeletric materials also show nonlinear polarization properties. 

 

Filtering 

Filters pass the desired portion of signals while rejecting the rest. Different filter topologies have different responses. Filters can be created with op-amps, resistors, inductors and capacitors. Capacitors used in a filter should be stable with voltage, temperature, and frequency, like C0G ceramics or film. 

 

Full Wave Rectifier 

A full wave rectifier is an electronic circuit that will take an alternating current input, such as line voltage, and turn it into a direct current output for use in things like consumer electronic devices. 

G

H

Heat Dissipation 

In electronics, heat dissipation is a process in which energy is transformed from some initial form and dissipated into heat. See also, Dissipation Factor (DF). 

 

High-Pass Filter 

A high-pass filter attenuates signals at frequencies below its designed cutoff frequency. A simple first-order passive filter is comprised of a series capacitor and a shunt resistor. 

 

High Power 

High power refers to applications that run on voltages exceeding 1000 V, such as power generation. Because of the inherent danger of these applications, devices used must meet public safety standards. 

 

High Reliability (Defense) 

Military and aerospace applications require components with higher reliability than commercial applications. These devices are specially designed to be robust in mission-critical applications, where commercial grade components may fail. “High-rel” components operate in harsh conditions such as high shock, high vibration, high moisture, and extreme temperatures. 

 

High Temperature 

Typical high temperature applications start at 150°C and can go over 200°C. High temperature components are designed to specifically operate and survive at these temperature ranges. 

Even though components are rated for these higher temperatures, when using them above 85°C, unique derating guidelines may still apply. 

 

High Voltage 

The level at which a voltage is considered “high” can vary depending on the application. For example, 50 V may be high for DC applications. AC applications, on the other hand, may consider high voltages to be above 400 V. 1,000 V could be classified as high voltage in power applications. 

 

Hold-Up 

Hold-up capacitor banks are used in circuits that must finish an operation after power has been removed. This is similar to the decoupling application. The difference is that decoupling only provides energy for transients lasting nanoseconds to microseconds. It is common to use polymer or supercapacitors as a hold-up bank to provide power for many milliseconds. 

 

Humidity, Steady-State, Low Voltage (HSSLV) 

HSSLV lot acceptance testing is defined in the MIL-PRF-123 specification. Both the requirement and a test method are available. 

www.dscc.dla.mil provides a downloadable copy of the MIL-PRF-123. 

Information about ceramic capacitors from KEMET, can be found in the MIL-PRF-123 Datasheet. 

I

Impedance (Z) 

Impedance is the combined effect of all resistive and reactive elements. Reactive elements include the capacitive and inductive reactance. 

Z = Impedance
R = Resistance
XC = Capacitive reactance
XL = Inductive reactance 

See also ESR and ESL. 

 

Insulation Resistance (IR) 

The amount of resistance provided by the dielectric layer is stated as the insulation resistance. It is determined by measuring the amount of current after applying a constant DC voltage. 

Insulation resistance is significant because it describes the strength of the dielectric layer.
Typically film and ceramic dielectrics will specify insulation resistance. 

 

Integrator 

An integrator is an electronic circuit that performs the mathematical function of integration. Its output voltage is proportional to the sum or integral of its input voltage over time. 

J

K

KEMET Power Solutions (KPS) 

KEMET Power Solutions (KPS) offers ceramic capacitors in a stacked package. Different configurations are available for commercial, automotive, industrial, and military applications. Packaging options range from off-the-shelf footprints to fully custom designs. 

 

KO-CAP® – Polymer Electrolytic Capacitors 

Polymer tantalum capacitors use a conductive polymer for their cathode layer. This gives them the volumetric efficiency of traditional tantalums but with significantly lower ESR and a non-ignition failure mode. 

L

Large Can Aluminum Electrolytic 

Large can aluminum electrolytic capacitors are available with both screw and snap-in terminals. These robust connections allow for high voltage (up to 500 V) and high ripple current applications. 

 

Leakage Current 

Leakage current is the small amount of current that a charged capacitor will allow to pass when voltage is applied. All dielectrics exhibit some amount of leakage current. Dielectrics with higher insulation resistance will have lower leakage. Typically, aluminum and tantalum dielectrics will specify leakage current. 

 

Linear Regulator 

Linear regulators are usually of the LDO variety. LDO is an acronym for low-dropout. LDOs are usually used for loads that draw relatively small amounts of current and that the output voltage is lower than the input voltage. The term “low-dropout” is a reference to the fact that LDO’s have very little dropout voltage, that is that it can operate when the input voltage and output voltage are very close. 

An LDO works by maintaining a FET in its linear region with respect to the load current by use of a feedback loop. This is effectively a voltage divider where the high-side resistance is dynamically adjusted with a changing load. An LDO can achieve better efficiency than a switching regulator where the required output voltage is close to input voltage. 

 

Low Pass Filter 

A low-pass filter attenuates signals at frequencies above its designed cut-off frequency. A simple first-order passive filter is comprised of a series resistor and a shunt capacitor. 

 

Low Voltage DC 

Low voltage DC designs are sub-100 V applications where the primary operating condition is DC. 

In many cases, passive components are used in filtering and decoupling applications supporting microprocessors, ASICs, FPGAs, memory and other high-performance ICs. 

M

Modelithics 

Modelithics provides simulation models for all types of RF & microwave components and semiconductor devices for use in popular Electronic Design Automation (EDA) tools. Modelithics reliably tracks how the component performance will change with various input parameters over a specified frequency range documented in a model information datasheet for each component. 

 

Moisture Sensitivity Level (MSL) 

Moisture Sensitivity Level (MSL) relates to the packaging and handling precautions for some semiconductors. The MSL is an electronic standard for the time period in which a moisture sensitive device can be exposed to ambient room conditions. Typically, at 30°C/85%RH at Level 1 and 30°C/60%RH at all other levels. 

N

O

Oscillating 

Oscillator circuits are used to generate periodic wave shapes such as sinusoidal, square or trapezoidal. Capacitors determine the frequency of the oscillations. RC (resistor-capacitor) oscillators or LC (inductor-capacitor) tanks can be used, depending on the frequency range. 

Components used in oscillators should be stable with temperature and voltage for reliable frequency output. 

P

Part/Process Change Notification (PCN) 

Definition: PCN is a document issued by a manufacturer to inform customers about a change to a mass-produced product or its manufacturing process. 

 

Paraelectric 

Paraelectricity is the ability of many materials to become polarized under an applied electric field. Unlike ferroelectricity, this can happen even if there is no permanent electric dipole in the material. 

 

Piezoelectric Effect 

Piezoelectricity, also referred to as the piezoelectric effect, is the ability of a material to generate a voltage and/or an electrical signal (noise) when subjected to an external mechanical stress or vibration. Synonymous with the term “microphonics”, MLCCs constructed of ferroelectric materials are piezoelectric in nature and can convert external stress, similarly to the way a microphone converts sound, into an electrical signal. 

See also, Electrostriction. 

 

PDN 

The PDN or Power Distribution Network is the circuit or circuits that supply power to all the components and peripherals of a system. Typically, PDNs include a combination of switchers and LDOs to meet the power demands of each part of the system efficiently. PDNs can combine both integrated and discrete implementations of regulators. In the world of motherboards and computing, PDNs are called Voltage Regulator Modules or VRMs. 

 

PMIC 

A PMIC or Power Management Integrated Circuit is a device that combines several voltage regulators into a single chip. A PMIC is usually the primary source of power delivery to all the sub-systems of a circuit. It provides a centralized location for all the voltage rails of a system. PMICs usually have a control interface back to the main processor of a system. With that control interface, the processor can tell the PMIC which voltage rails to turn on and when so that devices are only powered when needed. That level of control usually creates a more robust and efficient system. PMICs usually contain a combination of both switchers and LDOs. In recent years, the development of “Smart” PMICs has accelerated a great deal. Smart PMICs have a small microcontroller inside that will adjust the internal operating parameters of the PMIC’s rails in order to increase efficiency. 

 

PPAP 

KEMET’s Production Part Approval Process (PPAP) is used for verification to automotive customers and states that all design and specification requirements are properly understood and applied to the production process, and that the process has the potential to produce product that meets those requirements. The process is designed specifically to meet the requirements of the AIAG Production Part Approval Process reference manual. KEMET uses the Customer Interface database to describe requirements, define responsibilities, and retain documentation for the PPAP process. 

 

PPM 

PPM/°C is the unit of measure to express the temperature coefficient of capacitors (TCC). This specifies the fraction (expressed in parts per million per degrees centigrade) that its electrical characteristics will deviate when taken to a temperature above or below the operating temperature. 

 

Pulse Discharge 

Pulse Discharge surface mount capacitors deliver extremely fast and reliable high voltage and high temperature performance required for operation in harsh environments. Typical applications include high temperature pulse discharge circuits for munitions and down-hole oil exploration/perforation. 

Learn more about Pulse Discharge and see what Pulse Discharge Capacitors KEMET offers.

Q

R

Rated Voltage 

The rated voltage of a component is the maximum peak operating voltage that can be applied for continuous operating up to the rated temperature. For a capacitor, the rated voltage is the maximum voltage to which the device can be charged. Exceeding this may damage or destroy the capacitor. 

The specific parameters of each capacitor and capacitor family will determine its rated voltage. 

 

Relay 

A relay is an electrically operated switch, controlled by an electromagnet that allows current to flow from one circuit to another. 

 

RF Ceramic 

An RF capacitor is a capacitor whose characteristics are favorable at RF frequencies.  Materials are chosen and the design is optimized so that the capacitor’s characteristics are well suited at the higher frequencies.  By using copper instead of nickel for their electrode plates, RF ceramic capacitors have significantly lower ESR and a higher self-resonant frequency. High-Q is achieved by combing these electrodes with a low-loss C0G material. 

 

RoHS 

Restriction of Hazardous Substances Directive (RoHS) documents for KEMET’s products is available on from this page. 

S

S-Parameter 

Scattering Parameters or S-Parameters  are a tool used to describe the behavior of linear electrical networks. Depending on the network type S-parameters can describe properties such as input return loss, output return loss, forward gain, and reverse attenuation. 

S-parameters are usually a topic very closely related to RF applications, but due to the rising complexity of power distribution networks in circuit boards, S-parameters a being used to simulate the performance of the PDN. 

 

Sample and Hold 

Analog to digital converters (ADCs) require an input voltage to be stable while digitizing. Sample and hold circuits use a capacitor to maintain that voltage level while it is being sampled. 

 

Self-Healing 

The process of self-healing varies by dielectric type. In general, self-healing occurs when imperfections, flaws, or faults are repaired within the capacitor during normal operation. Once self-healing occurs, the capacitor becomes more robust. Commonly aluminum, film and polymer capacitors exhibit self-healing capabilities. 

 

Self-Resonance (SRF) 

A circuit containing an inductance and capacitance has a resonant frequency at the point where the capacitive and inductive reactance are equal. 

In a capacitor, the ESL provides the inductive reactance along with the inherent capacitance to create the self-resonance. 

 

Simulated Breakdown Screening (SBDS) 

Simulated Breakdown Screening (SBDS) is a KEMET patented process to screen out potentially weak devices from a production lot. Each capacitor is non-destructively tested to determine the potential breakdown voltage, without damaging the device. This ensures that only the most robust capacitors are shipped to the customer.
SBDS is often used in high-reliability industries such as medical or aerospace. 

 

STEP File 

A STEP file is an industry standard file type which is readable by most (and perhaps all) CAD software programs used by engineers to layout printed circuit boards and other end product types. Each STEP file in Component Edge is a dimensionally accurate, 3D mechanical representation of a KEMET component. 

To learn more about STEP files and how to download them, read a blog on 3D Capacitor Models with CapacitorEdge’s Latest Button: 3D STEP. 

 

Supercapacitors (EDLCs) 

Supercapacitors, or electrical double-layer capacitors, use the principle of an electrical double layer formed between the capacitor electrodes and electrolyte to maximize charge storage within a small volume. They can be used as power sources for small electronics and they have an advantage over rechargeable batteries because of the very low recharge time. 

 

Surface Mount Aluminum Electrolytic 

Sometimes called a V-chip, surface mount aluminum electrolytics provide a large amount of capacitance in a relatively small package. They tend to be rated from 10–50 V, with higher voltages available.
These capacitors are wound with alternating aluminum foils separated by a paper that is impregnated with an electrolyte. 

 

Surface Mount Ceramic (MLCC) 

Surface mount multilayer ceramic capacitors (MLCCs) comprise laminated layers of ceramic dielectric material interspersed with a metal electrode system. This allows large capacitance values in standard SMD chip sizes. They also come in a variety of ceramic dielectrics that allow for use
in various applications. 

 

Surface Mount Film 

Surface mount film capacitors are similar to through-hole film capacitors with the leads replaced by a lead-frame. Since these are typically used in reflow applications, the film used as the dielectric layer is typically polyester, PPS, or impregnated paper. 

For extra protection against moisture or extreme temperatures, encapsulated versions of the capacitors are available. 

T

Tantalum MnO2 

The MnO2 tantalum capacitor comprises an anode formed from sintered pure tantalum powder, a tantalum pentoxide (Ta2O5) dielectric, and cathode of manganese dioxide (MnO2). One advantage of these devices is that they have low leakage current. 

 

Temperature Coefficient of Capacitance (TCC) 

Temperature Coefficient of Capacitance (TCC) describes the maximum change in capacitance over a specified temperature range. The capacitance value stated by the manufacturer is established at a reference temperature of 25°C. TCC should always be considered for applications operating above or below this temperature. 

 

Temperature Rating 

Typically, an expected lifetime is stated for the maximum operating temperature. Operating a component beyond this temperature range may drastically reduce its life. 

Parameters of the component may change when approaching the limits of this range. Different
de-rating may be necessary within the range, as shown in this graph. 

 

Totem Pole Driver 

Also known as a push-pull output, this circuit is used to supply or sink current, based on the input. 

This circuit is used on the output stage of the general-purpose input/output (GPIO) pins of a microcontroller. 

 

Transient Liquid Phase Sintering (TLPS) 

Transient Liquid Phase Sintering (TLPS) is the low-temperature reaction of a low melting point metal or alloy with a high melting point metal or alloy to form a reacted metal matrix. 

TLPS forms a metallurgical bond between two surfaces. Depending on the allow, TLPS may have a re-melt temperature in excess of 600°. 

More information regarding TLPS can be found in this presentation on the Development and Characterization of High-Temperature MLCCs using Transient Liquid Phase Sintering (TLPS). 

U

U2J Capacitors 

U2J is an extremely stable dielectric material for Class I multilayer ceramic capacitors (MLCCs). Ceramic capacitors using the U2J dielectric retain over 99% of nominal capacitance at full rated voltage. When referenced to ambient temperature, U2J ceramic capacitors provide a predictable and linear change in capacitance. Additionally, U2J ceramic capacitors extend the available capacitance of Class I MLCCs into a range previously only available to Class II dielectric materials such as X5R and X7R 

V

Voltage Divider 

A voltage divider is a circuit that produces an output voltage as a fixed fraction of the applied voltage. The simplest voltage divider is a series network of two resistors, from which the output is taken at the connection between the resistors. 

W

Wave Shaping 

The time constant (τ) of an RC (resistor-capacitor) circuit can be used to shape waveforms. Changing R or C will change τ and thus change the shape of the output waveform. 

 

Wheatstone Bridge 

The Wheatstone bridge describes a circuit configuration that allows accurate measurement or calibration by comparing ratios. This eliminates the effects of variables such as resistor tolerance or power supply fluctuations. This topology can also be used to determine an unknown impedance (resistance) if the other three are known. 

X

X5R Ceramic 

The Electronics Components, Assemblies & Materials Association (EIA) characterizes X5R dielectric as a Class II materialComponents of this classification are a fixed ceramic dielectric, generally made of Barium Titanate (BaTiO3). Typically, they are used for bypass and decoupling applications. 

X5R exhibits a predictable change in capacitance with respect to time and voltage. As the ambient temperature changes, there is a minimal change in capacitance. Capacitance change is limited to ±15% from -55°C to +85°C. For more information about EIA Classifications, see this FAQ on Temperature Coefficients. 

This datasheet has more information about KEMET’s X5R Ceramic Capacitors. 

 

X7R Ceramic 

The Electronics Components, Assemblies & Materials Association (EIA) characterizes X7R dielectric as a Class II material. Components of this classification are a fixed ceramic dielectric, generally made of Barium Titanate (BaTiO3). Typically, they are used for bypass and decoupling applications. 

X7R exhibits a predictable change in capacitance with respect to time and voltage. As the ambient temperature changes, there is a minimal change in capacitance. Capacitance change is limited to ±15% from -55°C to +125°C. For more information about EIA Classifications, see this FAQ on Temperature Coefficients. 

This datasheet has more information about KEMET’s X7R Ceramic Capacitors. 

 

X/Y Safety Capacitors 

X/Y safety capacitors have been primarily used in AC applications as X/Y capacitors. They are specifically designed to meet public safety standards as mandated by organizations such as UL or CE. 

Often you will hear theses referred to as X1, X2, X3 or Y1, Y2, Y3, and Y4 capacitors. 

KEMET offers a wide range of X1, X2, Y1, and Y2 capacitors. 

 

 

X and Y Capacitors 

X and Y capacitors are safety-rated capacitors used in AC line EMI filters. X Capacitors are used across the line. Y Capacitors are connected from line to ground. EMI filters will use one X capacitor and two Y capacitors. These capacitors are designed to fail safely to mitigate shock hazard and/or fire. 

See Also, X/Y Safety Capacitors. 

Y

Z