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WR20, WR25

( Automotive )_V02

Jan.2011

MARKING

Size

±±±±5%

±±±±1%

2512, 2010

4-digits marking

4-digits marking

FUNCTIONAL DESCRIPTION

Product characterization

Standard values of nominal resistance are taken from the E96 & E24 series for resistors with a tolerance of

±5%

&

±1%. The values of the E24/E96 series are in accordance with “IEC publication 60063”.

Derating curve

The power that the resistor can dissipate depends on the operating temperature; see Fig.2

MOUNTING

Due to their rectangular shapes and small tolerances, Surface Mountable Resistors are suitable for handling by

automatic placement systems. Chip placement can be on ceramic substrates and printed-circuit boards (PCBs).

Electrical connection to the circuit is by individual soldering condition. The end terminations guarantee a reliable

contact.

SOLDERING CONDITION

The robust construction of chip resistors allows

them to be completely immersed in a solder bath

of 260

°C for 10 seconds. Therefore, it is possible

to mount Surface Mount Resistors on one side of

a PCB and other discrete components on the

reverse (mixed PCBs).

Surface

Mount

Resistors

are

tested

for

solderability at 235

°C during 2 seconds. The test

condition for no leaching is 260

°C for 30 seconds.

Typical examples of soldering processes that

provide reliable joints without any damage are

given in Fig 3.

Fig 3. Infrared soldering profile for Chip Resistors