T491R227M035AH Просмотр технического описания (PDF) - KEMET

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T491R227M035AH

Surface Mount Capacitors

KEMET 

SOLID TANTALUM CHIP CAPACITORS

TANTALUM MnO2 COMPONENT PERFORMANCE CHARACTERISTICS (con’t.)

20.0

10.0

10.0

Reference 1.0

at + 25°C

5.0

Reference

1.0 at 120 Hz

1.0

0.1

-60 -40 -20 0 +20 +40 +60 +80 +100 +125

Operating Temperature—ЊC

FIGURE 4 Typical Effect of Temperature upon

DC Leakage Current

DC leakage current decreases with decreasing

applied voltage.

1.0

0.1

1.0

100

1k

10k

Frequency — Hertz

FIGURE 6 Typical Effect of Frequency upon Dissipation

Factor

Dissipation factor is a very useful low frequency

(120 Hz) measurement of the resistive component

of a capacitor. It is the ratio of the equivalent series

resistance (ESR) to the capacitive reactance, (XC)

and is usually expressed as a percentage. It is

directly proportional to both capacitance and fre-

quency. Dissipation factor loses its importance at

higher frequencies, (above about 1 kHz), where

impedance (Z) and equivalent series resistance

(ESR) are the normal parameters of concern.

DF = R = 2␲fCR

XC

DF = Dissipation Factor

R = Equivalent Series

Resistance (Ohms)

XC = Capacitive Reactance

(Ohms)

f = Frequency (Hertz)

C = Series Capacitance

(Farads)

0.01

0.001

0

10 20 30 40 50 60 70 80 90

Percentage of Rated Voltage

FIGURE 5 Typical Effect of Applied Voltage on DC

Leakage Current.

100 110

DF is also referred to as tan ␦ or “loss tangent.”

The “Quality Factor,” “Q,” is the reciprocal of DF.

DF decreases with temperature above +25°C and

may also increase at lower temperatures.

Unfortunately, one general limit for DF cannot be

specified for all capacitance/voltage combinations,

nor can response to temperature be simply stated.

DC bias is not commonly used at room tempera-

ture, but is more commonly used at elevated tem-

peratures.

9. Dissipation Factor (DF)

Refer to part number tables for maximum DF

limits.

Dissipation factor is measured at 120 Hz, up to

1.0 volt rms maximum, and up to 2.0 volts DC

maximum at +25°C. The application of DC bias

causes a small reduction in DF, about 0.2% when

full rated voltage is applied. DF increases with

increasing frequency.

10. Equivalent Series Resistance (ESR) and

Impedance (Z)

Equivalent Series Resistance (ESR) is the pre-

ferred high-frequency statement of the resistance

unavoidably appearing in these capacitors. ESR

is not a pure resistance, and it decreases with

increasing frequency.

Total impedance of the capacitor is the vector

sum of capacitive reactance (XC) and ESR, below

resonance; above resonance total impedance is

the vector sum of inductive reactance (XL) and

ESR.

©KEMET Electronics Corporation, P.O. Box 5928, Greenville, S.C. 29606, (864) 963-6300

7

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