Datasheet

Data Sheet ADuM1300/ADuM1301
Rev. K | Page 27 of 32
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. In addition to the
testing performed by the regulatory agencies, Analog Devices
carries out an extensive set of evaluations to determine the
lifetime of the insulation structure within the ADuM1300/
ADuM1301.
Analog Devices performs accelerated life testing using voltage
levels higher than the rated continuous working voltage. Accel-
eration factors for several operating conditions are determined.
These factors allow calculation of the time to failure at the actual
working voltage. The values shown in Table 14 summarize the
peak voltage for 50 years of service life for a bipolar ac operating
condition and the maximum CSA/VDE approved working
voltages. In many cases, the approved working voltage is higher
than the 50-year service life voltage. Operation at these high
working voltages can lead to shortened insulation life in some
cases.
The insulation lifetime of the ADuM1300/ADuM1301 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 18, Figure 19, and Figure 20 illustrate these different
isolation voltage waveforms, respectively.
Bipolar ac voltage is the most stringent environment. The goal
of a 50-year operating lifetime under the ac bipolar 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, which allows operation at
higher working voltages while still achieving a 50-year service
life. The working voltages listed in Table 14 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 19
or Figure 20 should be treated as a bipolar ac waveform, and its
peak voltage should be limited to the 50-year lifetime voltage
value listed in Table 14.
Note that the voltage presented in Figure 19 is shown as sinusoidal
for illustration purposes only. It is meant to represent any voltage
waveform varying between 0 V and some limiting value. The
limiting value can be positive or negative, but the voltage
cannot cross 0 V.
Figure 18. Bipolar AC Waveform
Figure 19. Unipolar AC Waveform
Figure 20. DC Waveform
0V
RATED PEAK VOLTAGE
03787-021
0V
RATED PEAK VOLTAGE
03787-022
0V
RATED PEAK VOLTAGE
03787-023