ADM3053

Data Sheet

Rev. E | Page 16 of 18

(Pin 16 or Pin 20). The transition time of the CAN bus signals

are short as possible, allowing higher speed signaling. A shielded

cable is recommended to avoid EMI problems in high speed mode.

Slope control mode allows the use of unshielded twisted pair

wires or parallel pair wires as bus lines. The signal rise and fall

transition times are slowed to reduce EMI and ringing. The rise

INSULATION LIFETIME

All insulation structures eventually break down when subjected to

voltage stress over a sufficiently long period. The rate of insulation

degradation is dependent on the characteristics of the voltage

waveform applied across the insulation. Analog Devices conducts

an extensive set of evaluations to determine the lifetime of the

insulation structure within the ADM3053.

Accelerated life testing is performed using voltage levels higher

than the rated continuous working voltage. Acceleration factors for

several operating conditions are determined, allowing calculation

of the time to failure at the working voltage of interest. The values

shown in Table 5 summarize the peak voltages for 50 years of

service life in several operating conditions. In many cases, the

working voltage approved by agency testing is higher than the 50

year service life voltage. Operation at working voltages higher than

the service life voltage listed leads to premature insulation failure.

The insulation lifetime of the ADM3053 depends on the voltage

waveform type imposed across the isolation barrier. The iCoupler

insulation structure degrades at different rates, depending on

whether the waveform is bipolar ac, unipolar ac, or dc. Figure 29,

Figure 30, and Figure 31 illustrate these different isolation voltage

waveforms.

Bipolar ac voltage is the most stringent environment. A 50 year

operating lifetime under the bipolar ac condition determines

the Analog Devices recommended maximum working voltage.

In the case of unipolar ac or dc voltage, the stress on the insulation

is significantly lower. This allows operation at higher working

voltages while still achieving a 50 year service life. The working

voltages listed in Table 5 can be applied while maintaining the

50 year minimum lifetime, provided the voltage conforms to either

the unipolar ac or dc voltage cases. Any cross insulation voltage

waveform that does not conform to Figure 30 or Figure 31 must

be treated as a bipolar ac waveform, and its peak voltage must

be limited to the 50-year lifetime voltage value listed in Table 5.

0V

RATED PEAK VOLTAGE

Figure 29. Bipolar AC Waveform

0V

RATED PEAK VOLTAGE

Figure 30. DC Waveform

0V

RATED PEAK VOLTAGE

NOTES

1. THE VOLTAGE IS SHOWN AS SINUSODIAL FOR ILLUSTRATION

PURPOSES ONLY. IT IS MEANT TO REPRESENT ANY VOLTAGE

WAVEFORM VARYING BETWEEN 0 AND SOME LIMITING VALUE.

THE LIMITING VALUE CAN BE POSITIVE OR NEGATIVE, BUT THE

VOLTAGE CANNOT CROSS 0V.

Figure 31. Unipolar AC Waveform