ASM206E/ASM207E/ASM208E/ASM2±±E/ASM2±3E
burst of sparks as the relay contacts separate. The voltage
appearing on the line, therefore, consists of a burst of extremely
fast transient impulses. A similar effect occurs when switching
on fluorescent lights.
•
Classification 3: Temporary degradation or loss of function
or performance that requires operator intervention or
system reset.
Classification 4: Degradation or loss of function that is not
recoverable due to damage.
•
The fast transient burst test defined in IEC ±000-4-4 simulates
this arcing; its waveform is illustrated in Figure 29. It consists of
a burst of 2.5 kHz to 5 kHz transients repeating at 300 ms
intervals. It is specified for both power and data lines.
ADM2xxE products meet Classification 2 and have been tested
under worst-case conditions using unshielded cables. Data
transmission during the transient condition is corrupted, but it
can resume immediately following the EFT event without user
intervention.
V
C
R
D
L
R
M
HIGH
C
50Ω
OUTPUT
t
VOLTAGE
SOURCE
300ms
15ms
Z
C
S
C
5ns
V
Figure 30. IEC 1000-4-4 Fast Transient Generator
IEC 1000-4-3 RADIATED IMMUNITY
50ns
IEC ±000-4-3 (previously IEC 80±-3) describes the measure-
ment method and defines the levels of immunity to radiated
electromagnetic fields. It was originally intended to simulate the
electromagnetic fields generated by portable radio transceivers
or any other devices that generate continuous wave-radiated
EM energy. Its scope has since been broadened to include
spurious EM energy that can be radiated from fluorescent
lights, thyristor drives, inductive loads, and other sources.
t
0.2ms/0.4ms
Figure 29. IEC 1000-4-4 Fast Transient Waveform
Table 9.
V Peak (kV)
PSU
V Peak (kV)
I/O
Level
±
2
3
4
0.5
±
2
0.25
0.5
±
Testing for immunity involves irradiating the device with an EM
field. There are various methods of achieving this, including use of
anechoic chamber, stripline cell, TEM cell, and GTEM cell. A
stripline cell consists of two parallel plates with an electric field
developed between them. The device under test is placed within
the cell and exposed to the electric field. There are three severity
levels having field strengths ranging from ± V/m to ±0 V/m.
Results are classified in a similar fashion to those for IEC ±00044.
4
2
A simplified circuit diagram of the actual EFT generator is
illustrated in Figure 30.
The transients are coupled onto the signal lines using an EFT
coupling clamp. The clamp is ± m long and surrounds the cable
completely, providing maximum coupling capacitance (50 pF to
200 pF typical) between the clamp and the cable. High energy
transients are capacitively coupled onto the signal lines. Fast rise
times (5 ns), as specified by the standard, result in very effective
coupling. Because high voltages are coupled onto the signal
lines, this test is very severe. The repetitive transients can often
cause problems where single pulses do not. Destructive latch-up
can be induced due to the high energy content of the transients.
Note that this stress is applied while the interface products are
powered up and are transmitting data. The EFT test applies
hundreds of pulses with higher energy than ESD. Worst-case
transient current on an I/O line can be as high as 40 A.
•
•
Classification ±: Normal operation.
Classification 2: Temporary degradation or loss of function
that is self recoverable when the interfering signal is
removed.
•
•
Classification 3: Temporary degradation or loss of function
that requires operator intervention or system reset when
the interfering signal is removed.
Classification 4: Degradation or loss of function that is not
recoverable due to damage.
The ADM2xxE family of products easily meets Classification ± at
the most stringent requirement (Level 3). In fact, field strengths
up to 30 V/m showed no performance degradation, and error-
free data transmission continued even during irradiation.
Test results are classified according to the following:
•
Classification ±: Normal performance within speci-
fication limits.
•
Classification 2: Temporary degradation or loss of
performance that is self recoverable.
Rev. E | Page ±3 of 20
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