DocID023640 Rev 2

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AN4160

Description of the EMC standards for surge tests

14

2.3

Surge test levels

Surge levels should be selected according to application environment. Table 1 below

provides the different voltage levels and environment description according to

IEC61000 4 5:

Series resistance of the surge generator depends on the surge application mode:

•

When the surge is applied in differential mode (i.e. surge applied between lines), the

series resistance is 2

Ω

•

When the surge is applied in common mode (i.e. between a line and the ground),

series resistance is 12

As the surge current impacts on the power rating of the protection devices, the table below

shows the maximum peak current values depending on voltage level and series resistance.

Figure 6 shows how the surge is applied to the EUT in both differential and common-mode

configurations.

Table 1. Voltage levels and environment description according to IEC61000-4-5

Class

Environment

Voltage level

0

Well protected environment, often in a special room

25 V

1

Partially protected environment

500 V

2

Electrical environment where the cables are well separated, even at

short runs

1 kV

3

Electrical environment where power and signal cables run in parallel

2 kV

4

Electrical environment where the interconnections include outdoor

cables along with the power cable, and cables are used for both

electronics and electric circuits

4 kV

5

Electrical environment for electronic equipment connected to

telecommunication cables and overhead power lines in a non-densely

populated area

Same as class 4

Table 2. Surge current vs. source impedance and surge level

Class 0

25 V

Class 1

500 V

Class 2

1 kV

Class 3

2 kV

Class 4

4 kV

R = 12

Ω

2.1 A

42 A

84 A

167 A

334 A

R = 2

Ω

12.5 A

250 A

500 A

1000 A

2000 A