Datasheet ADUM1234 (Analog Devices) - 10

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ADuM1234 Data Sheet
The insulation lifetime of the ADuM1234 depends on the voltage
15V V 5V DD1 GND
waveform type imposed across the isolation barrier. The iCoupler
1 V 15V
insulation structure degrades at different rates depending on
DDA AND VDDB GNDA AND GNDB 15V ∆V
whether the waveform is bipolar ac, unipolar ac, or dc. Figure 15,
V ∆t DDA AND VDDB
Figure 16, and Figure 17 illustrate these different isolation voltage
∆V GNDA AND GNDB ∆t V 5V 15V
waveforms.
DD1 GND
3
1
-00 Bipolar ac voltage is the most stringent environment. The goal 920 06 Figure 12. Common-Mode Transient Immunity Waveforms, Input to Output of a 50-year operating lifetime under the bipolar ac condition determines the maximum working voltage recommended by Analog Devices.
15V V 15V DDA/VDDB
In the case of unipolar ac or dc voltage, the stress on the insulation
GNDA/GNDB
is significantly lower. This allows operation at higher working
V 15V DDB/VDDA GNDB/GNDA
voltages while still achieving a 50-year service life. The working
15V ∆V V ∆t
voltages listed in Table 8 can be applied while maintaining the
DDA/VDDB ∆V GNDA/GNDB
50-year minimum lifetime, provided that the voltage conforms
∆t V 15V 15V DDB/VDDA
to either the unipolar ac or dc voltage cases.
GNDA/GNDB
04 0 920- 06 Any cross-insulation voltage waveform that does not conform Figure 13. Common-Mode Transient Immunity Waveforms, to Figure 16 or Figure 17 should be treated as a bipolar ac wave- Between Outputs form and its peak voltage should be limited to the 50-year lifetime voltage value listed in Table 8.
VDDA/VDDB
Note that the voltage presented in Figure 16 is shown as sinu-
∆VDD
soidal for illustration purposes only. It is meant to represent any
∆t
voltage waveform varying between 0 V and some limiting value.
VDDA/VDDB
05 -0 The limiting value can be positive or negative, but the voltage
GNDA/GNDB GNDA/GNDB
920 06 cannot cross 0 V. Figure 14. Transient Immunity Waveforms, Output Supplies
RATED PEAK VOLTAGE INSULATION LIFETIME
4
0V
01 All insulation structures eventually break down when subjected 0- 92 06 to voltage stress over a sufficiently long period. The rate of insu- Figure 15. Bipolar AC Waveform lation degradation depends on the characteristics of the voltage waveform applied across the insulation. In addition to the testing
RATED PEAK VOLTAGE
performed by the regulatory agencies, Analog Devices conducts an extensive set of evaluations to determine the lifetime of the 15 0 0- 92 insulation structure within the ADuM1234.
0V
06 Analog Devices performs accelerated life testing using voltage Figure 16. Unipolar AC Waveform levels higher than the rated continuous working voltage. Accel- eration factors for several operating conditions are determined.
RATED PEAK VOLTAGE
These factors allow calculation of the time to failure at the actual 16 0 0- working voltage. 92
0V
06 Table 8 lists the peak voltages for 50 years of service life for Figure 17. DC Waveform a bipolar ac operating condition and the maximum working voltages recommended by Analog Devices. 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. Rev. A | Page 10 of 12 Document Outline Features Applications General Description Functional Block Diagram Table of Contents Revision History Specifications Electrical Characteristics Package Characteristics Regulatory Information Insulation and Safety-Related Specifications DIN V VDE V 0884-10 (VDE V 0884-10):2006-12 Insulation Characteristics Recommended Operating Conditions Absolute Maximum Ratings ESD Caution Pin Configuration and Function Descriptions Typical Perfomance Characteristics Applications Information Common-Mode Transient Immunity Insulation Lifetime Outline Dimensions Ordering Guide