Data Sheet

ADuM7223

POWER CONSUMPTION

The supply current at a given channel of the ADuM7223

isolator is a function of the supply voltage, channel data rate,

and channel output load.

For each input channel, the supply current is given by

For each output channel, the supply current is given by

where:

supply currents (mA).

per channel (mA/Mbps).

f is the input logic signal frequency (MHz, half of the input data

rate, NRZ signaling).

currents for each input and output channel corresponding to

of data rate for both outputs loaded with 2 nF capacitance.

INSULATION LIFETIME

All insulation structures eventually break down when subjected

to voltage stress over a sufficiently long period. The rate of insu-

lation 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 ADuM7223.

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 Table 7 summarize the peak voltage for

50 years of service life for a bipolar ac operating condition. In

many cases, the approved working voltage is higher than a 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 ADuM7223 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 20, Figure 21, and Figure 22 illustrate these

different isolation voltage waveforms.

A bipolar ac voltage environment is the worst case for the

iCoupler products and is the 50-year operating lifetime that

Analog Devices recommends for 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. Treat any cross-

insulation voltage waveform that does not conform to Figure 21

or Figure 22 as a bipolar ac waveform, and limit its peak voltage

to the 50-year lifetime voltage value listed in Table 7.

Note that the voltage presented in Figure 21 is shown as sinu-

soidal 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 20. Bipolar AC Waveform

Figure 21. Unipolar AC Waveform

Figure 22. DC Waveform

0V

RATED PEAK VOLTAGE

0V

RATED PEAK VOLTAGE

0V

RATED PEAK VOLTAGE

Rev. A | Page 13 of 16