7.5

Adhesive application

Thin or insufficient adhesive causes chips to loosen or become disconnected during curing.

Low viscosity of the adhesive causes chips to slip after mounting. It is advised to consult the

manufacturer of the adhesive on proper usage and amounts of adhesive to use.

7.6

Selection of flux

Used flux should have less than or equal to 0.1 wt % of halogenated content, since flux residue

after soldering could lead to corrosion of the termination and/or increased leakage current on the

surface of the component. Strong acidic flux must not be used. The amount of flux applied should

be carefully controlled, since an excess may generate flux gas, which in turn is detrimental to sol-

derability.

7.7

Storage of CTVSs

Solderability is guaranteed for one year from date of delivery for multilayer varistors, CeraDiodes

and ESD/EMI filters (half a year for chips with AgPd terminations) and two years for SHCV and

CU components, provided that components are stored in their original packages.

Storage temperature:

25

°C to +45 °C

Relative humidity:

≤75% annual average, ≤95% on 30 days a year

The solderability of the external electrodes may deteriorate if SMDs and leaded components are

stored where they are exposed to high humidity, dust or harmful gas (hydrogen chloride, sulfurous

acid gas or hydrogen sulfide).

Do not store SMDs and leaded components where they are exposed to heat or direct sunlight.

Otherwise the packing material may be deformed or SMDs/ leaded components may stick togeth-

er, causing problems during mounting.

After opening the factory seals, such as polyvinyl-sealed packages, it is recommended to use the

SMDs or leaded components as soon as possible.

7.8

Placement of components on circuit board

Especially in the case of dual-wave soldering, it is of advantage to place the components on the

board before soldering in that way that their two terminals do not enter the solder bath at different

times.

Ideally, both terminals should be wetted simultaneously.

7.9

Soldering cautions

An excessively long soldering time or high soldering temperature results in leaching of the outer

electrodes, causing poor adhesion and a change of electrical properties of the varistor due to

the loss of contact between electrodes and termination.

Wave soldering must not be applied for MLVs designated for reflow soldering only.

Keep the recommended down-cooling rate.

SMD disk varistors (CU varistors)

Automotive series

Page 21 of 28

Please read Cautions and warnings and

Important notes at the end of this document.