Sutnan Capacitor Information

Tantalum capacitors are used in smaller electronic devices, including portable telephones, pagers, personal computers (PCs), and automotive electronics. They differ in terms of form factor, technology, and capacitance type. Leaded tantalum capacitors have leads for connections to circuits. Surface mount or chip tantalum capacitors do not. For both types of products, technology choices include single layer, multilayer, and wound. Single layer tantalum capacitors use a monolithic dielectric. Multilayer products are small in size and made of many layers. They provide good frequency characteristics as well as excellent temperature stability. Wound tantalum capacitors are built by winding foils, sometimes by hand. In terms of capacitance type, there are two choices: fixed and variable. Fixed tantalum capacitors have a nonadjustable capacitance value. Variable tantalum capacitors can be set with a potentiometer or other adjustment mechanism. 

Selecting tantalum capacitor requires an analysis of performance specifications such as capacitance range, capacitance tolerance, DC rated voltage range (WVDC), equivalent series resistance (ESR), leakage current, dissipation factor and operating temperature. Capacitance measures the ability to store energy, given as C = K A/D, where A is the area of the electrodes, D is their separation, and K is a function of the dielectric between the electrodes. Normally, capacitance tolerance is measured as a percentage of capacitance. DC rated voltage range (WVDC) is the maximum continuous DC voltage that may be continuously applied to a tantalum capacitor at any temperature between the lower category temperature and the rated temperature. Equivalent series resistance (ESR) represents the extent to which tantalum capacitors act like resistors when charging and discharging. Dissipation factor (DF) is the ratio between the resistive and the reactive part of the impedance submitted to a sinusoidal voltage of specified frequency.

There are three main packaging specifications for tantalum capacitors: lead or termination type, mounting style, and packing method. Choices for lead type include surface mount technology (SMT), axial, radial, flying, tab, screw, gull wing, and J-leads. Mounting styles include SMT as well as through-hole technology (THT), bolt mounts, bracket mounts, and pole mounts. There are three main packing methods for tantalum capacitors: tape reel, tray or rail, and shipping tube or stick magazine. Polarized, non-polarized, and self-healing products are also commonly available.

Ceramic capacitors have a dielectric made of ceramic materials. General specifications include configuration, capacitance type, and technology. There are two basic configurations for ceramic capacitors: leaded and surface mount. Leaded ceramic capacitors have leads for connections to circuits. Surface mount capacitors or chip capacitors do not. Ceramic capacitor technologies are categorized as monolithic, multilayer, or wound. Monolithic components use a dielectric made of a single layer. Multilayer devices are made of many layers and are small in size. They provide excellent temperature stability and frequency characteristics. Wound capacitors are built by winding foils, sometimes by hand. In terms of technology, there are two choices: fixed and variable. Fixed ceramic capacitors have a nonadjustable capacitance value. With variable ceramic capacitors, specific capacitance values are set with a potentiometer. 

Ceramic capacitor differ in terms of electrostatic material, the insulation between the plates of a multilayer capacitor. Ceramic COG (NPO) capacitors have a high Q, low K, temperature-compensated dielectric and stable electrical properties under varying voltage, temperature, frequency and time. They are suitable for low-lost circuits and for timing and tuning applications. Ceramic X7R (BX) capacitors have moderate K values and are temperature-stable. They exhibit moderate changes in electrical properties under conditions of changing temperature, voltage, and frequency. Ceramic Z5U capacitors are Class III devices with a dielectric that exhibits a maximum capacitance change of +22% - 56% over an operating temperature range of +10 °C to + 85 °C. Ceramic capacitors with other types of electrostatic material are also available. 

Selecting Ceramic capacitor requires an analysis of performance specifications and packaging specifications. Products also differ in terms of features and compliance with Restriction of Hazardous Substances (RoHS). Performance specifications for ceramic capacitors include capacitance range, capacitance tolerance, DC rated voltage range (WVDC), test voltage, dissipation factor, insulation resistance, and equivalent series resistance (ESR). There are three categories of packaging specifications: lead or termination type, mounting style, and packing method. Choices for lead type include surface mount technology (SMT), axial, radial, flying, tab, screw, gull-wing, and J-leads. There are five mounting styles: through-hole technology (THT), surface mount technology (SMT), bolt, bracket, and pole. Tape reel, tray or rail, and shipping tube or stick magazine are common packing methods for Ceramic capacitors.