DocID024789 Rev 2

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AN4310

Capacitor comparison

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Capacitor comparison

Table 2 compares the most important characteristics that need to be reviewed when

The PPS (polyphenylene sulfide) dielectric and the NPO ceramic capacitors performs

excellently in all categories. The PET (metalized polyester) and the PEN (metalized

polyphenylene naphthalate) capacitors also perform quite well and can be used in all touch

sensing applications.

Tantalum capacitors should be avoided as they have a very high dissipation factor and a

high effective series resistance (ESR). X7R ceramic capacitors can be used in certain

applications when a less sensitive level is required.

Table 2. Characteristics of film SMD capacitors

PET

PEN

PPS

NPO

X7R

Tantalum

Operating temperature (°C)

−55 to 125

−55 to 125

−55 to 140

−55 to 125

−55 to 125

−55 to 125

ΔC/C with temperature (°C)

±5

±5

±1.5

±1

±1

±10

Dissipation factor

(%)

1 kHz

0.8

0.8

0.2

0.1

2.5

8

10 kHz

1.5

1.5

0.25

0.1

-

-

100 kHz

3.0

3.0

0.5

0.1

-

-

Dielectric absorption (%)

0.5

1

0.05

0.6

2.5

-

ESR

Low

Low

Very low

Low

Moderate to

high

High

Reliability

High

High

High

High

Moderate

Low