adum1300 Analog Devices, Inc., adum1300 Datasheet - Page 17

• Manufacturer Part Number: adum1300
• Description: Triple-channel Digital Isolators
• 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 from the
ADuM130x transformers. Figure 17 expresses these allowable
current magnitudes as a function of frequency for selected
distances. As seen, the ADuM130x 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, one would have to place a 0.5 kA current 5 mm away
from the ADuM130x to affect the component’s operation.
1000.00
100.000
100.00
10.000
10.00
1.000
0.100
0.010
1.00
0.10
0.01
0.001
Figure 16. Maximum Allowable External Magnetic Flux Density
1k
1k
DISTANCE = 100mm
for Various Current-to-ADuM130x Spacings
Figure 17. Maximum Allowable Current
DISTANCE = 5mm
10k
10k
MAGNETIC FIELD FREQUENCY (Hz)
MAGNETIC FIELD FREQUENCY (Hz)
100k
100k
1M
1M
DISTANCE = 1m
10M
10M
100M
100M
Rev. C | Page 17 of 20
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.
POWER CONSUMPTION
The supply current at a given channel of the ADuM130x isola-
tor 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
ply currents (mA).
To calculate the total I
currents for each input and output channel corresponding to
I
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 12 provide total
I
ADuM1300/ADuM1301 channel configurations.
r
DDI (D)
DDI (Q)
DD1
DD1
L
DDO
is the input stage refresh rate (Mbps).
is output load capacitance (pF).
I
I
I
I
and I
and I
DDI
DDI
DDO
DDO
is the output supply voltage (V).
, I
, I
DDO (D)
DDO (Q)
= I
= I
= I
= (I
DD2
DD2
DDI (Q)
DDI (D)
DDO (Q)
DDO (D)
are calculated and totaled. Figure 6 and Figure 7
supply current as a function of data rate for
are the input and output dynamic supply currents
are the specified input and output quiescent sup-
× (2f – f
+ (0.5 × 10
DD1
r
) + I
and I
DDI (Q)
−3
) × C
ADuM1300/ADuM1301
DD2
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