ADuM1410/ADuM1411/ADuM1412
For example, at a magnetic field frequency of 1 MHz, the
maximum allowable magnetic field of 0.2 kgauss induces a
voltage of 0.25 V at the receiving coil. This is about 50% of the
sensing threshold and does not cause a faulty output transition.
Similarly, if such an event occurs during a transmitted pulse
(and was of the worst-case polarity), it reduces the received
pulse from >1.0 V to 0.75 V—still well above the 0.5 V sensing
threshold of the decoder.
Note that at combinations of strong magnetic field and high
frequency, any loops formed by printed circuit board traces
could induce error voltages sufficiently large enough to trigger
the thresholds of succeeding circuitry. Care should be taken in
the layout of such traces to avoid this possibility.
POWER CONSUMPTION
The supply current at a given channel of the ADuM141x
isolator is a function of the supply voltage, the data rate of the
channel, and the output load of the channel.
The preceding magnetic flux density values correspond to
specific current magnitudes at given distances from the
ADuM141x transformers. Figure 19 expresses these allowable
current magnitudes as a function of frequency for selected
distances. As shown, the ADuM141x is extremely immune and
can be affected only by extremely large currents operated at
high frequency very close to the component. For the 1 MHz
example noted, a 0.5 kA current needed to be placed 5 mm
away from the ADuM141x to affect the operation of the
component.
For each input channel, the supply current is given by
IDDI = IDDI (Q)
DDI = IDDI (D) × (2f − fr) + IDDI (Q)
f ≤ 0.5 fr
f > 0.5 fr
I
For each output channel, the supply current is given by
IDDO = IDDO (Q) f ≤ 0.5 fr
I
DDO = (IDDO (D) + (0.5 × 10−3) × CL × VDDO) × (2f − fr) + IDDO (Q)
f > 0.5 fr
1000
DISTANCE = 1m
where:
DDI (D), IDDO (D) are the input and output dynamic supply currents
100
I
per channel (mA/Mbps).
CL is the output load capacitance (pF).
10
V
DDO is the output supply voltage (V).
DISTANCE = 100mm
f is the input logic signal frequency (MHz); it is half of the input
1
data rate expressed in units of Mbps.
DISTANCE = 5mm
fr is the input stage refresh rate (Mbps).
0.1
I
DDI (Q), IDDO (Q) are the specified input and output quiescent
supply currents (mA).
0.01
1k
10k
100k
1M
10M
100M
To calculate the total VDD1 and VDD2 supply current, the supply
currents for each input and output channel corresponding to
MAGNETIC FIELD FREQUENCY (Hz)
Figure 19. Maximum Allowable Current for Various
Current-to-ADuM141x Spacings
VDD1 and VDD2 are calculated and totaled. Figure 8 and Figure 9
provide per-channel supply currents as a function of data rate
for an unloaded output condition. Figure 10 provides per-
channel supply current as a function of data rate for a 15 pF
output condition. Figure 11 through Figure 15 provide total
VDD1 and VDD2 supply current as a function of data rate for
ADuM1410/ADuM1411/ADuM1412 channel configurations.
Rev. E | Page 19 of 20
ADI [ ADI ]
