AN3361

Definition of the electrical transients and tests

Doc ID 018589 Rev 1

3/15

from +24 V to +48 V with a pulse duration up to 400 ms and a minimum series resistance

that can be as low as 0.5

Ω.

Figure 2.

ISO 7637-2 pulse 5b clamped load-dump

Table 1.

ISO 7637-2 main surge pulses

Pulse

Origin

Pulse

polarity

12V system

N° 1

Supply disconnection from inductive loads

Negative

-100 V

2 ms

N° 2a

The sudden interruption of current through a

device connected in parallel with the device

under test (DUT) due to the inductance of the

wiring harness

Positive

+50 V

50 µs

N° 2b

DC motor acting as a generator after the

ignition is switched off

Positive

10 V

2 s

N° 3a

Occur as a result of the switching processes

Negative

-150 V

100 µs

N° 3b

Occur as a result of the switching processes

Positive

100 V

200 µs

N° 4

Voltage reduction caused by energizing the

starter-motor of internal combustion engines

Negative

-7 V

40 ms

N° 5b

Load-dump transient occurring in the event

of a discharged battery being disconnected

while the alternator is generating charging

current, case with auto-protected alternator

Positive

87 V

Application

dependant

Table 2.

Parameter values for test pulse 5b

Parameter

12 V system

65 V to 87 V

As specified by customer

40 ms to 400 ms

0.5 to 4

Ω

0.1xUS

t

U