adum3200 Analog Devices, Inc., adum3200 Datasheet - Page 16

• Manufacturer Part Number: adum3200
• Description: Dual-channel, Digital Isolators, Enhanced System-level Esd Reliability
• Manufacturer: Analog Devices, Inc.

ADuM3200/ADuM3201
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 had 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
ADuM320x transformers. Figure 14 expresses these allowable
current magnitudes as a function of frequency for selected
distances. As seen, the ADuM320x are extremely 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, one would have to place a 0.5 kA current 5 mm away
from the ADuM320x to affect the component’s operation.
0.001
1000
0.01
0.01
Figure 13. Maximum Allowable External Magnetic Flux Density
100
100
0.1
0.1
10
10
1
1
1k
1k
Figure 14. Maximum Allowable Current for Various
DISTANCE = 100mm
10k
DISTANCE = 5mm
Current-to-ADuM320x Spacings
10k
MAGNETIC FIELD FREQUENCY (Hz)
MAGNETIC FIELD FREQUENCY (Hz)
100k
100k
1M
1M
DISTANCE = 1m
10M
10M
100M
100M
Rev. 0 | Page 16 of 20
Note that at combinations of strong magnetic fields and high
frequencies, any loops formed by printed circuit board traces
could induce sufficiently large error voltages to trigger the
threshold 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 ADuM320x
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
currents for each input and output channel corresponding to
I
channel input supply currents as a function of data rate. Figure 7
and Figure 8 provide per-channel output supply currents as a
function of data rate for an unloaded output condition and for a
15 pF output condition, respectively. Figure 9 through Figure 11
provide total I
rate for ADuM3200 and ADuM3201 channel configurations.
r
DDI (D)
DDI (Q)
DD1
L
DDO
is the input stage refresh rate (Mbps).
is the output load capacitance (pF).
and I
I
I
I
I
is the output supply voltage (V).
DDI
DDI
DDO
DDO
, I
, I
DDO (D)
DDO (Q)
= I
= I
= I
= (I
DD2
DDI (Q)
DDI (D)
DDO (Q)
are calculated and totaled. Figure 6 provides per-
DDO (D)
are the input and output dynamic supply currents
are the specified input and output quiescent
DD1
× (2f – f
and I
+ (0.5 × 10
DD1
DD2
r
) + I
and I
supply current as a function of data
DDI (Q)
−3
DD2
) × C
supply current, the supply
L
V
DDO
) × (2f – f
r
) + I
f ≤ 0.5f
f > 0.5f
f ≤ 0.5f
f > 0.5f
DDO (Q)
r
r
r
r