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53

CWR11

Vishay Sprague

Document Number 40011

Revision 31-Jan-05

For technical questions, contact tantalum@vishay.com

1.

A-C Ripple Current: The maximum allowable ripple

current shall be determined from the formula:

where,

P =

Power Dissipation in Watts @ + 25°C as given

in the table in Paragraph Number 5 (Power

Dissipation).

at the specified frequency.

2.

A-C Ripple Voltage: The maximum allowable ripple

voltage shall be determined from the formula:

or, from the formula:

P =

Power Dissipation in Watts @ + 25°C as

given in the table in Paragraph Number 5

(Power Dissipation).

at the specified frequency.

Z =

The capacitor impedance at the specified

frequency.

2.1

The sum of the peak AC voltage plus the 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: These capacitors are capable of

withstanding peak voltages in the reverse direction

equal to 10% of the DC rating at + 25°C, 5% of the

DC rating at + 85°C and 1% of the DC rating at

+ 125°C.

4.

Temperature Derating: If these capacitors are to be

operated at temperatures above + 25°C, the

permissible rms ripple current or voltage 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

P

where,

P

GUIDE TO APPLICATION

Case Code

Maximum Permissible

Power Dissipation

@ + 25

(Watts) in free air

A

B

C

D

0.075

0.085

0.110

0.150

Temperature

Derating Factor

+ 25°C

+ 85°C

+ 125°C

1.0

0.9

0.4

surface. Non-sinusoidal ripple current may produce

heating effects which differ from those shown. It is

important that the equivalent

established when calculating permissible operating

levels. (Power Dissipation calculated using + 25°C

temperature rise.)

6.

Printed Circuit Board Materials: Type CWR11

is compatible with commonly used printed circuit

board materials (alumina substrates, FR4, FR5,

G10, PTFE-fluorocarbon and porcelanized steel).

7.

Attachment:

7.1

Solder Paste: The recommended thickness of the

solder paste after application is .007" ± .001"

[.178mm ± .025mm]. Care should be exercised in

selecting the solder paste. The metal purity should

be as high as practical. The flux (in the paste) must

be active enough to remove the oxides formed on the

metallization prior to the exposure to soldering

heat. In practice this can be aided by extending

the solder preheat time at temperatures below the

liquidous state of the solder.

7.2

Soldering: Capacitors can be attached by

conventional soldering techniques - vapor phase,

infrared reflow, wave soldering and hot plate

methods. The Soldering Profile chart shows

maximum recommended time/temperature

conditions for soldering. Attachment with a

soldering iron is not recommended due to the

difficulty of controlling temperature and time at

temperature.

8.

Cleaning (Flux Removal) After Soldering: The

CWR11 is compatible with all 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.

8.1

When using ultrasonic cleaning, the board may

resonate if the output power is too high. This vibration

can cause cracking or a decrease in the adherence

of the termination. DO NOT EXCEED 9W/l @ 40kHz

for 2 minutes.