TM8

Vishay Sprague

Solid Tantalum Chip Capacitors

Leadframeless Molded

www.vishay.com

Document Number: 40133

46

Revision: 22-Jun-10

GUIDE TO APPLICATION

1.

A-C Ripple Current: The maximum allowable ripple

current shall be determined from the formula:

where,

P =

Power dissipation in watts at + 25 °C as

given in the table in paragraph number 5

(power dissipation).

The capacitor equivalent series resistance

at the specified frequency.

2.

A-C Ripple Voltage: The maximum allowable ripple

voltage shall be determined from the formula:

or, from the formula:

where,

P =

Power dissipation in watts at + 25 °C as

given in the table in paragraph number 5

(power dissipation).

The capacitor equivalent series resistance

at 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: 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

surface. Non-sinusoidal ripple current may produce

heating effects which differ from those shown. It is

when calculating permissible operating levels. (Power

Dissipation calculated using + 25

°C temperature

rise.)

6.

Printed Circuit Board Materials: Molded capacitors

are 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 0.007" ± 0.001"

[0.178 mm ± 0.025 mm]. 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,

convection reflow, infrared reflow, wave soldering

and hot plate methods. The Soldering Profile charts

show recommended time/temperature conditions for

soldering.

Preheating

is

recommended.

The

recommended maximum ramp rate is 2 °C per

second. 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.

7.2.1 Backward and Forward Compatibility: Capacitors

with SnPb or 100 % tin termination finishes can be

soldered using SnPb or lead (Pb)-free soldering

processes.

8.

Cleaning (Flux Removal) After Soldering: Molded

capacitors are 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 at 40 kHz for

2 minutes.

9.

Recommended Mounting Pad Geometries: Proper

mounting pad geometries are essential for successful

solder connections. These dimensions are highly

process sensitive and should be designed to

minimize component rework due to unacceptable

solder joints. The dimensional configurations shown

are the recommended pad geometries for both wave

and reflow soldering techniques. These dimensions

are intended to be a starting point for circuit board

designers and may be fine tuned if necessary based

upon the peculiarities of the soldering process and/or

circuit board design.

TEMPERATURE

DERATING FACTOR

+ 25 °C

1.0

+ 85 °C

0.9

+ 125 °C

0.4

I

rms

P

R

ESR

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

=

V

rms

Z

P

R

ESR

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

=

V

rms

I

rms

Z

×

=