Data Sheet ADuM3400W/ADuM3401W/ADuM3402W
Rev. B | Page 17 of 20
To calculate the total I
DD1
and I
DD2
supply current, the supply
currents for each input and output channel corresponding to
V
DD1
and V
DD2
are calculated and totaled. Figure 8 provides the
per-channel input supply current as a function of the data rate.
Figure 9 and Figure 10 provide the per-channel supply output
current as a function of the data rate for an unloaded output
condition and for a 15 pF output condition, respectively. Figure 11
through Figure 15 provide the total V
DD1
and V
DD2
supply
current as a function of the data rate for ADuM3400W/
ADuM3401W/ADuM3402W channel configurations.
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 ADuM3400W/
ADuM3401W/ADuM3402W.
Analog Devices performs accelerated life testing using voltage
levels higher than the rated continuous working voltage.
Acceleration 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
Figure 21 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 ADuM3400W/ADuM3401W/
ADuM3402W 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 21, Figure 22, and
Figure 23 illustrate these different isolation voltage waveforms.
Bipolar ac voltage is the most stringent environment. The goal
of a 50-year operating lifetime under the ac bipolar condition
determines the recommended maximum working voltage of
Analog Devices.
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 19 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 22
or Figure 23 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 19.
Note that the voltage presented in Figure 22 is shown as sinusoi-
dal 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.
0V
RATED PEAK VOLTAGE
11000-021
Figure 21. Bipolar AC Waveform
0V
RATED PEAK VOLTAGE
11000-022
Figure 22. Unipolar AC Waveform
0V
RATED PEAK VOLTAGE
11000-023
Figure 23. DC Waveform
