08051A101BA2A datasheet(91/99 Pages) AVX

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General Description

Typical Cap. Change vs. D.C. Volts

X7R

Typical Cap. Change vs. Temperature

X7R

Effects of Time – Class 2 ceramic capacitors change

capacitance and dissipation factor with time as well as

temperature, voltage and frequency. This change with time is

known as aging. Aging is caused by a gradual re-alignment

of the crystalline structure of the ceramic and produces an

exponential loss in capacitance and decrease in dissipation

factor versus time. A typical curve of aging rate for

semistable ceramics is shown in Figure 6.

If a Class 2 ceramic capacitor that has been sitting on the

shelf for a period of time, is heated above its curie point,

(125°C for 4 hours or 150°C for 1⁄2 hour will suffice) the part will

de-age and return to its initial capacitance and dissi-pation

factor readings. Because the capacitance changes

rapidly, immediately after de-aging, the basic capacitance

measurements are normally referred to a time period

sometime after the de-aging process. Various manufacturers

use different time bases but the most popular one is one day

or twenty-four hours after “last heat.” Change in the aging

curve can be caused by the application of voltage and

other stresses. The possible changes in capacitance due to

de-aging by heating the unit explain why capacitance changes

are allowed after test, such as temperature cycling, moisture

resistance, etc., in MIL specs. The application of high voltages

such as dielectric withstanding voltages also tends to de-age

capacitors and is why re-reading of capacitance after 12 or

24 hours is allowed in military specifications after dielectric

strength tests have been performed.

Effects of Frequency – Frequency affects capacitance and

impedance characteristics of capacitors. This effect is much

more pronounced in high dielectric constant ceramic

formulation than in low K formulations. AVX’s SpiCap

software generates impedance, ESR, series inductance,

series resonant frequency and capacitance all as functions

of frequency, temperature and DC bias for standard chip

sizes and styles. It is available free from AVX and can be

downloaded for free from AVX website: www.avx.com.

25%

50%

75%

100%

Percent Rated Volts

-5

-10

-15

-20

0VDC

-55 -35

-15

+25 +45 +65 +85 +105 +125

Temperature Degrees Centigrade

+20

+10

-10

-20

-30

Figure 4

Figure 5

100

1000 10,000 100,000

Hours

+1.5

-1.5

-3.0

-4.5

-6.0

-7.5

Characteristic

Max. Aging Rate %/Decade

C0G (NP0)

X7R, X5R

Y5V

None

Figure 6

Typical Curve of Aging Rate

X7R

08051A101BA2A Datasheet(PDF) 91 Page - AVX Corporation

08051A101BA2A Datasheet(HTML) 91 Page - AVX Corporation

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