Conformal Coated Guide

www.vishay.com

Vishay Sprague

Revision: 12-Sep-17

11

Document Number: 40150

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

GUIDE TO APPLICATION

1.

AC Ripple Current: the maximum allowable ripple

current shall be determined from the formula:

where,

P =

power dissipation in W at +25 °C as given in

the tables in the product datasheets (Power

Dissipation).

the specified frequency

2.

AC Ripple Voltage: the maximum allowable ripple

voltage shall be determined from the formula:

or, from the formula:

where,

P =

power dissipation in W at +25 °C as given in

the tables in the product datasheets (Power

Dissipation).

the specified frequency

Z =

the capacitor impedance at the specified

frequency

2.1

The sum of the peak AC voltage plus the applied DC

voltage shall not exceed the DC voltage rating of the

capacitor.

2.2

The sum of the negative peak AC voltage plus

the applied DC voltage shall not allow a voltage

reversal exceeding 10 % of the DC working voltage

at +25 °C.

3.

Reverse Voltage: solid tantalum capacitors are not

intended for use with reverse voltage applied.

However, they have been shown to be capable of

withstanding momentary reverse voltage peaks of up

to 10 % of the DC rating at 25 °C and 5 % of the DC

rating at +85 °C.

4.

Temperature Derating: if these capacitors are to be

operated at temperatures above +25 °C, the

permissible RMS ripple current shall be calculated

using the derating factors as shown:

5.

Power Dissipation: power dissipation will be

affected by the heat sinking capability of the

mounting surface. Non-sinusoidal ripple current may

produce heating effects which differ from those

be

established

when

calculating

permissible

operating levels. (Power dissipation calculated using

derating factor (see paragraph 4)).

6.

Attachment:

6.1

Soldering:

capacitors

can

be

attached

by

conventional

soldering

techniques,

convection,

infrared reflow, wave soldering and hot plate

methods. The soldering profile chart shows typical

recommended time / temperature conditions for

soldering. Preheating is recommended to reduce

thermal stress. The recommended maximum preheat

rate is 2 °C/s. Attachment with a soldering iron is not

recommended due to the difficulty of controlling

temperature and time at temperature. The soldering

iron must never come in contact with the capacitor.

7.

Recommended Mounting Pad Geometries: the nib

must have sufficient clearance to avoid electrical

contact

with

other

components.

The

width

dimension indicated is the same as the maximum

width of the capacitor. This is to minimize lateral

movement.

8.

Cleaning

(Flux

Removal)

After

Soldering:

commonly used solvents such as TES, TMS, Prelete,

Chlorethane, Terpene and aqueous cleaning media.

However, CFC / ODS products are not used in the

production

of

these

devices

and

are

not

recommended.

Solvents

containing

methylene

chloride or other epoxy solvents should be avoided

since these will attack the epoxy encapsulation

material.

TEMPERATURE

DERATING FACTOR

+25 °C

1.0

+85 °C

0.9

+125 °C

0.4

I

RM S

P

R

ESR

------------

=

V

RMS

I

RM S

x

Z

=

V

RM S

Z

P

R

ESR

------------

=