adum2200 Analog Devices, Inc., adum2200 Datasheet - Page 17

• Manufacturer Part Number: adum2200
• Description: Dual-channel Digital Isolators, 5 Kv
• Manufacturer: Analog Devices, Inc.

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
ADuM220x transformers. Figure 15 expresses these allowable
current magnitudes as a function of frequency for selected
distances. As can be seen, the ADuM220x 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 previously, one would have to place a 0.5 kA current
5 mm away from the ADuM220x to affect operation of the
component.
Note that at combinations of strong magnetic field and high
frequency, any loops formed by printed circuit board traces can
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
for Various Current-to-ADuM220x Spacings
Figure 15. Maximum Allowable Current
DISTANCE = 5mm
10k
MAGNETIC FIELD FREQUENCY (Hz)
100k
1M
DISTANCE = 1m
10M
100M
Rev. A | Page 17 of 20
POWER CONSUMPTION
The supply current at a given channel of the ADuM220x
isolator is a function of the supply voltage, the channel’s data
rate, and the channel’s output load.
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
each input and output channel corresponding to I
are calculated and totaled. Figure 6 and Figure 7 provide per-
channel supply currents as a function of data rate for an
unloaded output condition. Figure 8 provides per-channel
supply current as a function of data rate for a 15 pF output
condition. Figure 9 through Figure 11 provide total I
as a function of data rate for ADuM2200/ADuM2201 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
DDI
DDI
DDO
DDO
is the output supply voltage (V).
, I
, I
DDO (D)
DDO (Q)
= I
= I
= I
= (I
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
) + I
and I
−3
ADuM2200/ADuM2201
DDI (Q)
) × C
DD2
, the supply currents for
L
× V
DDO
) × (2f − f
DD1
DD1
r
and I
) + I
and I
f ≤ 0.5f
f ≤ 0.5f
f > 0.5f
f > 0.5f
DDO (Q)
DD2
DD2
r
r
r
r