–8–

REV. 0

ADM483E

The ADM483E has been tested under worst case conditions

using unshielded cables, and meets Classification 2 at severity

Level 4. Data transmission during the transient condition is

corrupted, but it may be resumed immediately following the

EFT event without user intervention.

RADIATED IMMUNITY (IEC1000-4-3)

IEC1000-4-3 (previously IEC801-3) describes the measurement

method and defines the levels of immunity to radiated electro-

magnetic fields. It was originally intended to simulate the electro-

magnetic fields generated by portable radio transceivers or any

other device that generates continuous wave radiated electromag-

netic energy. Its scope has since been broadened to include

spurious EM energy, which can be radiated from fluorescent

lights, thyristor drives, inductive loads, etc.

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.

These consist essentially of two parallel plates with an electric

field developed between them. The device under test is placed

between the plates and exposed to the electric field. There

are three severity levels having field strengths ranging from

1 V to 10 V/m. Results are classified in a similar fashion to those

for IEC1000-4-2.

1. Normal Operation.

2. Temporary Degradation or loss of function that is self-

recoverable when the interfering signal is removed.

3. Temporary degradation or loss of function that requires

operator intervention or system reset when the interfering

signal is removed.

4. Degradation or loss of function that is not recoverable due to

damage.

The ADM483E comfortably meets Classification 1 at the most

stringent (Level 3) requirement. In fact, field strengths up to

30 V/m showed no performance degradation and error-free data

transmission continued even during irradiation.

Table VI.

Level

Field Strength

V/m

11

23

310

EMI EMISSIONS

The ADM483E contains internal slew rate limiting in order to

minimize the level of electromagnetic interference generated.

Figure 25 shows an FFT plot when transmitting a 150 kHz

data stream.

10

0%

100

90

10dB/DIV

500kHz/DIV

0

5MHz

Figure 25. Driver Output Waveform and FFT Plot Trans-

mitting @ 150 kHz

As may be seen, the slew limiting attenuates the high frequency

components. EMI is therefore reduced, as are reflections due to

improperly terminated cables.

EN55022, CISPR22 defines the permitted limits of radiated

and conducted interference from Information Technology

Equipment (ITE).

The objective is to control the level of emissions, both con-

ducted and radiated.

For ease of measurement and analysis, conducted emissions are

assumed to predominate below 30 MHz, while radiated

emissions predominate above this frequency.

CONDUCTED EMISSIONS

This is a measure of noise that is conducted onto the mains

power supply. The noise is measured using a LISN (Linc

Impedance Stabilizing Network) and a spectrum analyzer. The

test setup is illustrated in Figure 26. The spectrum analyzer is

set to scan the spectrum from 0 MHz to 30 MHz. Figure 27

shows that the level of conducted emissions from the

ADM483E are well below the allowable limits.

SPECTRUM

ANALYSER

DUT

LISN

PSU

Figure 26. Conducted Emissions Test Setup