ADuM2400ARIZ AD [Analog Devices], ADuM2400ARIZ Datasheet - Page 19
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ADuM2400ARIZ
Manufacturer Part Number
ADuM2400ARIZ
Description
Quad-Channel Digital Isolators
Manufacturer
AD [Analog Devices]
Datasheet
1.ADUM2400ARIZ.pdf
(24 pages)
Data Sheet
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 were to occur during a transmitted
pulse (and was of the worst-case polarity), it would reduce the
received pulse from >1.0 V to 0.75 V—still well above the 0.5 V
sensing threshold of the decoder.
The preceding magnetic flux density values correspond to
specific current magnitudes at given distances away from the
ADuM240x transformers. Figure 20 expresses these allowable
current magnitudes as a function of frequency for selected
distances. As can be seen, the ADuM240x is immune and can
be affected only by extremely large currents operated at high
frequency and very close to the component. For the 1 MHz
example noted, place a 0.5 kA current 5 mm away from the
ADuM240x to affect the component’s operation.
Note that at combinations of strong magnetic field and high
frequency, any loops formed by printed circuit board traces
could induce sufficiently large error voltages to trigger the
thresholds of succeeding circuitry. Care should be taken in
the layout of such traces to avoid this possibility.
1000
0.01
100
0.1
10
1
1k
DISTANCE = 100mm
Figure 20. Maximum Allowable Current for
Various Current-to-ADuM240x Spacings
DISTANCE = 5mm
10k
MAGNETIC FIELD FREQUENCY (Hz)
100k
1M
DISTANCE = 1m
10M
100M
Rev. D | Page 19 of 24
POWER CONSUMPTION
The supply current at a given channel of the ADuM240x isolator is
a function of the supply voltage, the data rate of the channel,
and the output load of the channel.
For each input channel, the supply current is given by:
For each output channel, the supply current is given by:
where:
I
per channel (mA/Mbps).
C
V
f is the input logic signal frequency (MHz, half of the input data
rate, NRZ signaling).
f
I
supply currents (mA).
To calculate the total I
input and output channel corresponding to I
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 the total I
data rate for the ADuM2400/ADuM2401/ ADuM2402 channel
configurations.
r
DDI (D)
DDI (Q)
L
DDO
is the input stage refresh rate (Mbps).
is the output load capacitance (pF).
I
I
I
I
is the output supply voltage (V).
DDI
DDI
DDO
DDO
, I
, I
DDO (D)
DDO (Q)
= I
= I
= I
= (I
ADuM2400/ADuM2401/ADuM2402
DDI (Q)
DDI (D)
DDO (Q)
DDO (D)
are the input and output dynamic supply currents
are the specified input and output quiescent
× (2f − f
+ (0.5 × 10
DD1
r
and I
) + I
-3
DDI (Q)
DD2
× C
, the supply currents for each
L
V
DD1
DDO
and I
) × (2f − f
DD1
DD2
and I
as a function of
r
) + I
DD2
DDO (Q)
are
f ≤ 0.5f
f ≤ 0.5f
f > 0.5f
f > 0.5f
r
r
r
r