6

7

•Pre-heating and cooling

In the reflow soldering method, a full pre-heating at the proper

temperature is necessary to dry and activate solder paste.

Tomb-stoning can be reduced by preheating at 150~180℃ for

more than 1 minute. Also when cooling is done by dipping into

solvent, care should be taken to keep the temperature difference

within 150℃.

•Standard Reflow Soldering Condition

Soldering must be carried out without exceeding the approved

soldering temperature and time shown within the shaded area

of the right graph. This prevents the terminations from leaching

and characteristics from deteriorating. When soldering is

repeated, the allowed time is the accumulated time.

•Standard solder amount

When a PCB is warped, mechanical stress applied to the chip should be reduced, and for doing so, care should be taken not to

use excessive amount of solder on the PCB. In case of the reflow method, the thickness of the coated solder paste is controlled to

When using a soldering iron or any other soldering operation, the permissible temperature and time should not be exceeded

that in the reflow soldering. In other to prevent the external terminations from leaching and characteristics from deteriorating,

the tip of the soldering iron should not touch the chip component (ceramic element, resin case, etc.). Soldering with a soldering

iron and correcting with a soldering iron can be performed right the following conditions.

Temperature at tip

Soldering iron output

End of soldering iron

Note

350

℃ Max.

20-Watt Max.

Ø3mm Max.

Do not directly touch the chip by the tip of the iron.

Item

Condition

Ceramic Substrate

Inner Electrode

Resistor

Glass Coat

Protective Coat

Terminal Coat

Ni Plate

Sn Plate

Ag / Cu

Ag-Pd / Cu-Ni

Polymer / Glass

Ni-Cr Alloy

Ni

Sn

Name

No.

Main Substance

< Reflow Soldering>

•Tombstoning and Prevention

When reflow soldering, or especially vapor phase soldering (VPS), small chip components of less than RC3216 type may break

away from solder and stand on end. This is commonly known as tombstoning or the Manhattan phenomenon.

- Preventing tombstoning

Keep land size as small as possible.

Keep the pre-heating conditions properly

( Pre-heating temperature : 150 ~ 180°, Pre-heating time : more than 1 min.)

Keep the solder paste quantity not too much and uniform for every lands.

Keep the position of chips properly.

At around the soldering temperature, keep minimize the difference of the temperature between the electrodes of a chip.

Reflow Soldering

Iron Soldering

General Structure of the Chip Resistor

Pre-heating

217

℃

Soldering

Temp.(

℃)

200

℃

150

℃

Gradual Cooling

in the air

245

±10℃

10 sec. max.

Time(sec.)

The specifications and designs contained herein may be subject to change without notice.

Please contact our sales representatives or product engineers before order.

General Structure

Operation

Notes

Example of land

Pattern Design

Recommended

Soldering Conditions

General Structure

General

Precision

Jumper

Low ohms

(RC Series)

Low ohms

(RUT Series)

Ultra Low Ohms

(RU Series)

Ultra Low Ohms

(RUK Series)

Ultra Low Ohms

(RUW Series)

Arrays

(CONVEX Type)

Arrays

(CONCAVE Type)

Arrays

(FLAT Type)

Arrays for

Memory Modules

Attenuator

Characteristics

Performance

Packaging

Standard

Resistance Value