MULTILAYER CERAMIC CAPACITORS/AXIAL & RADIAL LEADED
Multilayer ceramic capacitors are available in a variety of physical sizes and configurations, including leaded devices and surface mounted chips. Leaded styles include molded and conformally coated parts with axial and radial leads. However, the basic capacitor element is similar for all styles. It is called a chip and consists of formulated dielectric materials which have been cast into thin layers, interspersed with metal electrodes alternately exposed on opposite edges of the laminated structure. The entire structure is fired at high temperature to produce a monolithic block which provides high capacitance values in a small physical volume. After firing, conductive terminations are applied to opposite ends of the chip to make contact with the exposed electrodes. Termination materials and methods vary depending on the intended use.
TEMPERATURE CHARACTERISTICS Class III: General purpose capacitors, suitable Ceramic dielectric materials can be formulated with a wide range of characteristics. The EIA standard for for by-pass coupling or other applications in which ceramic dielectric capacitors (RS-198) divides ceramic dielectric losses, high insulation resistance and dielectrics into the following classes: stability of capacitance characteristics are of little or no importance. Class III capacitors are similar to Class II capacitors except for temperature characteristics, Class I: Temperature compensating capacitors, which are greater than ± 15%. Class III capacitors suitable for resonant circuit application or other applihave the highest volumetric efficiency and poorest cations where high Q and stability of capacitance charstability of any type. acteristics are required. Class I capacitors have predictable temperature coefficients and are not effected by voltage, frequency or time. They are made KEMET leaded ceramic capacitors are offered in from materials which are not ferro-electric, yielding the three most popular temperature characteristics: superior stability but low volumetric efficiency. Class I C0G: Class I, with a temperature coefficient of 0 ± capacitors are the most stable type available, but have 30 ppm per degree C over an operating the lowest volumetric efficiency. temperature range of - 55°C to + 125°C (Also known as “NP0”). X7R: Class II, with a maximum capacitance Class II: Stable capacitors, suitable for bypass change of ± 15% over an operating temperature or coupling applications or frequency discriminating range of - 55°C to + 125°C. circuits where Q and stability of capacitance charZ5U: Class III, with a maximum capacitance acteristics are not of major importance. Class II change of + 22% - 56% over an operating temcapacitors have temperature characteristics of ± 15% perature range of + 10°C to + 85°C. or less. They are made from materials which are ferro-electric, yielding higher volumetric efficiency but less stability. Class II capacitors are affected by Specified electrical limits for these three temperature temperature, voltage, frequency and time. characteristics are shown in Table 1.
SPECIFIED ELECTRICAL LIMITS
PARAMETER Dissipation Factor: Measured at following conditions: C0G — 1 kHz and 1 vrms if capacitance > 1000 pF 1 MHz and 1 vrms if capacitance ≤ 1000 pF X7R — 1 kHz and 1 vrms* or if extended cap range 0.5 vrms Z5U — 1 kHz and 0.5 vrms Dielectric Strength: 2.5 times rated DC voltage. Insulation Resistance (IR): At rated DC voltage, whichever of the two is smaller Temperature Characteristics: Range, °C Capacitance Change without DC voltage
* 1 MHz and 1 vrms if capacitance ≤ 100 pF on military product.
TEMPERATURE CHARACTERISTICS C0G X7R Z5U
0.15%
2.5%
4.0%
Pass Subsequent IR Test 1,000 MΩ-µF or 100 GΩ -55 to +125 0 ± 30 ppm/°C 1,000 MΩ-µF or 100 GΩ -55 to +125 ±15% 1,000 MΩ-µF or 10 GΩ +10 to +85 +22%, -56%
Table I
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Multlayer Ceramic Capacitors
CERAMIC CONFORMALLY COATED/AXIAL & RADIAL
PERFORMANCE CHARACTERISTICS FOR STANDARD AND HIGH VOLTAGE
GENERAL SPECIFICATIONS
Working Voltage: Axial (WVDC) C0G – 50 & 100 X7R – 50 & 100 Z5U – 50 & 100 Radial (WVDC) 50, 100, 200, 500, 1k, 1.5k, 2k, 2.5k, 3k 50, 100, 200, 500, 1k, 1.5k, 2k, 2.5k, 3k 50 & 100
ENVIRONMENTAL
Vibration: EIA RS-198, Method 304, Condition D (10-2000Hz; 20g) Shock: EIA RS-198, Method 305, Condition I (100g) Life Test: EIA RS-198, Method 201, Condition D. £ 200V C0G – 200% of rated voltage @ +125°C X7R – 200% of rated voltage @ +125°C Z5U – 200% of rated voltage @ +85°C ³ 500V C0G – rated voltage @ +125°C X7R – rated voltage @ +125°C Post Test Limits @ 25°C are: Capacitance Change: C0G (£ 200V) – +3% or 0.25pF, whichever is greater. C0G (³ 500V) – +3% or 0.50pF, whichever is greater. X7R – + 20% of initial value (2) Z5U – + 30% of initial value (2) Dissipation Factor: C0G – 0.15% maximum X7R – 2.5% maximum Z5U – 4.0% maximum Insulation Resistance: C0G – 10k Megohm or 100 Megohm x µF, whichever is less. ³1kV tested @ 500V. X7R – 10k Megohm or 100 Megohm x µF, whichever is less. ³1kV tested @ 500V. Z5U – 1k Megohm or 100 Megohm x µF, whichever is less. Moisture Resistance: EIA RS-198, Method 204, Condition A (10 cycles without applied voltage.) Post Test Limits @ 25°C are: Capacitance Change: C0G (£ 200V) – +3% or 0.25pF, whichever is greater. C0G (³ 500V) – +3% or 0.50pF, whichever is greater. X7R – + 20% of initial value (2) Z5U – + 30% of initial value (2) Dissipation Factor: C0G – 0.25% maximum X7R – 3.0% maximum Z5U – 4.0% maximum Insulation Resistance: C0G – 10k Megohm or 100 Megohm x µF, whichever is less. £500V test @ rated voltage, ³1kV test @ 500V. X7R – 10k Megohm or 100 Megohm x µF, whichever is less. ³500V test @ rated voltage, >1kV test @ 500V. Z5U – 1k Megohm or 100 Megohm x µF, whichever is less. Thermal Shock: EIA RS-198, Method 202, Condition B (C0G & X7R: -55°C to +125°C); Condition A (Z5U: -55°C to 85°C)
Temperature Characteristics: C0G – 0 ± 30 PPM / °C from - 55°C to + 125°C (1) X7R – ± 15% from - 55°C to + 125°C Z5U – + 22% / -56% from + 10°C to + 85°C Capacitance Tolerance: C0G – ±0.5pF, ±1%, ±2%, ±5%, ±10% X7R – ±10%, ±20%, +80% / -20%, +100% / -0% Z5U – ±20%, +80% / -20% Construction: Epoxy encapsulated - meets flame test requirements of UL Standard 94V-0. High-temperature solder - meets EIA RS-198, Method 302, Condition B (260°C for 10 seconds) Lead Material: 100% matte tin (Sn) with nickel (Ni) underplate and steel core. Solderability: EIA RS-198, Method 301, Solder Temperature: 230°C ±5°C. Dwell time in solder = 7 ± ½ seconds. Terminal Strength: EIA RS-198, Method 303, Condition A (2.2kg)
ELECTRICAL
Capacitance @ 25°C: Within specified tolerance and following test conditions. C0G – > 1000pF with 1.0 vrms @ 1 kHz £ 1000pF with 1.0 vrms @ 1 MHz X7R – with 1.0 vrms @ 1 kHz Z5U – with 1.0 vrms @ 1 kHz Dissipation Factor @ 25°C: Same test conditions as capacitance. C0G – 0.15% maximum X7R – 2.5% maximum Z5U – 4.0% maximum Insulation Resistance @ 25°C: EIA RS-198, Method 104, Condition A
