ADM202E/ADM1181A

Rev. C | Page 11 of 16

Table 4. IEC1000-4-2 Compliance Levels

Level

Contact Discharge

Air Discharge

1

2 kV

2 kV

2

4 kV

4 kV

3

6 kV

8 kV

4

8 kV

15 kV

Table 5. ADM202E/ADM1181A ESD Test Results

ESD Test Method

I/O Pins

MIL-STD-883B

±15 kV

IEC1000-4-2

Contact

±8 kV

Air

±15 kV

FAST TRANSIENT/BURST TESTING (IEC1000-4-4)

IEC1000-4-4 (previously 801-4) covers electrical fast transient

(EFT)/burst immunity. Electrical fast transients occur as a result

of arcing contacts in switches and relays. The tests simulate the

interference generated when, for example, a power relay

disconnects 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 burst 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 17. 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.

300ms

15ms

t

V

5ns

0.2/0.4ms

50ns

V

t

Figure 21. IEC1000-4-4 Fast Transient Waveform

A simplified circuit diagram of the actual EFT generator is

illustrated in Figure 22.

The transients are coupled onto the signal lines using an EFT

coupling clamp. The clamp, which is 1 m long, completely

surrounds the cable, providing maximum coupling capacitance

(50 pF to 200 pF typ) between the clamp and the cable. High

energy transients are capacitively coupled to the signal lines.

Fast rise times (5 ns), as specified by the standard, result in very

effective coupling. This test is very strenuous because high voltages

are coupled onto the signal lines. The repetitive transients 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 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.

HIGH

VOLTAGE

SOURCE

L

50

Ω

OUTPUT

Figure 22. IEC1000-4-4 Fast Transient Generator

Test results are classified according to the following:

•

Classification 1: Normal performance within specifi-

cation limits

•

Classification 2: Temporary degradation or loss of

performance that is self-recoverable

•

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 ADM202E/ADM1181A meet Classification 2 and have

been tested under worst-case conditions using unshielded

cables. Data transmission during the transient condition is

corrupted, but can resume immediately following the EFT event

without user intervention.