29

04/00

9.4

IEC climatic category

lEC 60068 -1, Appendix A, defines a method of specifying the climatic category by three groups of

numbers delimited by slash characters.

1st group of numbers:

Absolute value of the lower category temperature

test Aa (cold) in accordance with IEC 60068-2-1

2nd group of numbers:

Upper category temperature

test Ba (dry heat) in accordance with IEC 60068 -2-2

test duration: 16 h

3rd group of numbers:

Number of days denoting the test duration for

test Ca (damp heat, steady-state) in accordance with IEC 60068-2-3

at (93 + 2/– 3) % rel. humidity and an ambient temperature of 40

°C

10

Sizes

The sizes of surface-mount components

are encoded using a four-digit coding system.

The code differs depending on the standard which it is based on.

The American EIA standards require the length and width to be stated in hundredths of an inch, in

European standards and in the IEC draft standards, these dimensions are encoded in tenths of a

millimeter. The following table sumarizes the sizes:

Length

× width

(mm)

EIA

IEC/EN

1,0

× 0,5

0402

1005

1,6

× 0,8

0603

1608

2,0

× 1,2

0805

2012

2,5

× 2,0

1008

2520

3,2

× 2,5

1210

3225

4,5

× 3,2

1812

4532

5,6

× 5,0

2220

5650

Example:

55/085/56

– 55

°C

+ 85

°C

56 days

General Technical Information