Data Sheet ADuM3200/ADuM3201
Rev. F | Page 19 of 24
POWER CONSUMPTION
The supply current at a given channel of the ADuM3200/
ADuM3201 isolator is a function of the supply voltage, the
channel data rate, and the channel output load.
For each input channel, the supply current is given by
I
DDI
= I
DDI (Q)
f ≤ 0.5f
r
I
DDI
= I
DDI (D)
× (2f − f
r
) + I
DDI (Q)
f > 0.5f
r
For each output channel, the supply current is given by
I
DDO
= I
DDO (Q)
f ≤ 0.5f
r
I
DDO
= (I
DDO (D)
+ (0.5 × 10
−3
) × C
L
V
DDO
) × (2f − f
r
) + I
DDO (Q)
f > 0.5f
r
where:
I
DDI (D)
, I
DDO (D)
are the input and output dynamic supply currents
per channel (mA/Mbps).
C
L
is the output load capacitance (pF).
V
DDO
is the output supply voltage (V).
f is the input logic signal frequency (MHz, half of the input data
rate, NRZ signaling).
f
r
is the input stage refresh rate (Mbps).
I
DDI (Q)
, I
DDO (Q)
are the specified input and output quiescent
supply currents (mA).
To calculate the total I
DD1
and I
DD2
supply current, the supply
currents for each input and output channel corresponding to
I
DD1
and I
DD2
are calculated and totaled. Figure 6 provides per-
channel input supply currents as a function of data rate.
Figure 7 and Figure 8 provide per-channel output supply
currents as a function of data rate for an unloaded output
condition and for a 15 pF output condition, respectively.
Figure 9 through Figure 11 provide total I
DD1
and I
DD2
supply current as a function of data rate for ADuM3200
and ADuM3201 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 depends upon 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 ADuM3200/ADuM3201.
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 31 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.
The insulation lifetime of the ADuM3200/ADuM3201 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 15, Figure 16, and Figure 17 illustrate these different
isolation voltage waveforms.
A bipolar ac voltage environment is the most stringent. 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. This allows operation at higher working
voltages while still achieving a 50-year service life. The working
voltages listed in Table 31 can be applied while maintaining the
50-year minimum lifetime, provided that the voltage conforms
to either the unipolar ac or dc voltage cases. Any cross-insulation
voltage waveform that does not conform to Figure 16 or Figure 17
must be treated as a bipolar ac waveform and the peak voltage
must be limited to the 50-year lifetime voltage value listed in
Table 31.
Note that the voltage presented in Figure 16 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
05927-015
Figure 15. Bipolar AC Waveform
0V
RATED PEAK VOLTAGE
05927-016
Figure 16. Unipolar AC Waveform
0V
RATED PEAK VOLTAGE
05927-017
Figure 17. DC Waveform
