T22

www.vishay.com

Vishay

Revision: 13-May-2020

8

Document Number: 40187

THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT

7.1 The maximum leakage current for any capacitor shall

not exceed the maximum value in μA listed in the

Standard Ratings table for each capacitor.

Note

• Leakage current varies with applied voltage. See graph next

column for the appropriate adjustment factor

8.

Low Temperature Impedance: the impedance of any

capacitor at -55 °C at 120 Hz, shall not exceed the

values given in the Standard Ratings table.

9.

Life Test: capacitors are capable of withstanding a

2000 h life test at a temperature of +85 °C or +125 °C at

the applicable rated DC working voltage.

9.1 Following the life test, the capacitors shall be returned

to 25 °C ± 5 °C. The leakage current, measured at

the

+85 °C rated voltage, shall not be in excess of

the original requirement; the capacitance value shall

not exceed 150 % of the initial requirement; the

capacitance value shall not change more than + 10 % /

- 20 % from the initial measurement.

10.

Ripple Life Test at +85 °C: capacitors shall be tested

in

accordance

with

military

specification

MIL-PRF-39006 except that:

a) Operation conditions: this test shall be run at a

frequency of 40 kHz ± 2 kHz sinusoidal and at the

RMS ripple current levels specified in the Standard

Ratings table.

b) Applied DC voltage shall be reduced so that the

peak AC voltage plus DC voltage shall not exceed

the rated voltage of the capacitor in either the

forward or reverse direction.

10.1 When tested as specified above, capacitors shall meet

the following requirements:

a) The DC leakage current at +25 °C and at +85 °C

shall not exceed the original requirements.

b) The capacitance shall not change more than ± 15 %

from the initial measured value.

c) The dissipation factor shall not exceed the original

requirements.

d) Visual examination: There shall be no damage,

obliteration of marking or leakage of electrolyte.

GUIDE TO APPLICATION

1. AC Ripple Current: subjecting a capacitor to an AC

voltage causes an AC current to flow through it. The

amplitude of the current is dependent on the impedance

of the capacitor at the frequency of the applied signal:

where:

I = ripple current

V = applied AC voltage

Z = impedance of capacitor (frequency dependent)

This current causes heating in the capacitor because of

applied frequency). This heating or power dissipation, is

one of the limiting factors of the capacitor’s ripple current

rating.

These power dissipation ratings are based on a

calculated +50 °C internal temperature rise in still air. The

maximum allowable ripple currents given in the Standard

Ratings table are based on these ratings and the

maximum equivalent series resistance at that frequency.

The relationship is written as follows:

where:

P = maximum power

I = maximum ripple current

R = equivalent series resistance

Therefore:

where:

R is in



P is in W

TYPICAL LEAKAGE CURRENT FACTOR

RANGE

0

10

20

30 40 50 60

90 100

70 80

1.0

0.9

0.8

0.6

0.5

0.7

0.4

0.3

0.2

0.09

0.08

0.06

0.05

0.07

0.04

0.03

0.02

0.1

0.01

PERCENT OF RATED VOLTAGE

I

V

Z

---

=

PI

2

R

=

I

P

R

----

=