ADM202E/ADM1181A
Table I. IEC1000-4-2 Compliance Levels
Level
1
2
3
4
Contact Discharge
2 kV
4 kV
6 kV
8 kV
Air Discharge
2 kV
4 kV
8 kV
15 kV
A simplified circuit diagram of the actual EFT generator is illus-
trated in Figure 16.
The transients are coupled onto the signal lines using an EFT
coupling clamp. The clamp is 1 m long and it completely sur-
rounds the cable providing maximum coupling capacitance
(50 pF to 200 pF typ) 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. This test is very severe since high voltages are
coupled onto the signal lines. The repetitive transients can often
cause problems where single pulses don’t. Destructive latchup
may be induced due to the high energy content of the tran-
sients. Note that this stress is applied while the interface prod-
ucts 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.
R
M
C
D
Table II. ADM202E/ADM1181A ESD Test Results
ESD Test Method
MIL-STD-883B
IEC1000-4-2
Contact
Air
I/O Pins
±
15 kV
±
8 kV
±
15 kV
Other Pins
±
3 kV
FAST TRANSIENT BURST TESTING (IEC1000-4-4)
IEC1000-4-4 (previously 801-4) covers electrical fast-transient/
burst (EFT) immunity. Electrical fast transients occur as a re-
sult of arcing contacts in switches and relays. The tests simulate
the interference generated when for example a power relay dis-
connects an inductive load. A spark is generated due to the well
known back EMF effect. In fact the spark consists of a burst of
sparks as the relay contacts separate. The voltage appearing on
the line therefore consists of a bust of extremely fast transient
impulses. A similar effect occurs when switching on fluorescent
lights.
The fast transient burst test defined in IEC1000-4-4 simulates
this arcing and its waveform is illustrated in Figure 11. It con-
sists 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.
V
HIGH
VOLTAGE
SOURCE
R
C
L
50Ω
OUTPUT
C
C
Z
S
Figure 16. IEC1000-4-4 Fast Transient Generator
Test results are classified according to the following:
1. Normal performance within specification limits.
2. Temporary degradation or loss of performance that is
self-recoverable.
3. Temporary degradation or loss of function or performance
that requires operator intervention or system reset.
4. Degradation or loss of function that is not recoverable due
to damage.
The ADM202E/ADM1181A have been tested under worst case
conditions using unshielded cables and meet Classification 2.
Data transmission during the transient condition is corrupted,
but it may be resumed immediately following the EFT event
without user intervention.
t
300ms
V
5ns
15ms
50ns
t
0.2/0.4ms
Figure 15. IEC1000-4-4 Fast Transient Waveform
–8–
REV. 0
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