adum5401 Analog Devices, Inc., adum5401 Datasheet - Page 19

• Manufacturer Part Number: adum5401
• Description: Quad-channel Isolators With Integrated Dc-to-dc Converter
• Manufacturer: Analog Devices, Inc.

The preceding magnetic flux density values correspond to specific
current magnitudes at given distances from the ADuM5401/
ADuM5402/ADuM5403/ADuM5404 transformers. Figure 26
expresses these allowable current magnitudes as a function
of frequency for selected distances. As shown in Figure 26,
the ADuM5401/ ADuM5402/ADuM5403/ADuM5404 are
extremely immune and can be affected only by extremely large
currents operated at high frequency very close to the compo-
nent. For the 1 MHz example, a 0.5 kA current would need to
be placed 5 mm away from the ADuM5401/ADuM5402/
ADuM5403/ADuM5404 to affect component operation.
Note that in combinations of strong magnetic field and high
frequency, any loops formed by printed circuit board traces
could induce error voltages sufficiently large to trigger the
thresholds of succeeding circuitry. Care should be taken in
the layout of such traces to avoid this possibility.
POWER CONSUMPTION
The V
data channels, as well as to the power converter. For this reason,
the quiescent currents drawn by the data converter and the
primary and secondary I/O channels cannot be determined
separately. All of these quiescent power demands have been
combined into the I
total I
operating current; the dynamic current, I
the I/O channels; and any external I
0.01
100
Figure 26. Maximum Allowable Current for Various Current-to-
DD1
DD1
0.1
1k
10
1
ADuM5401/ADuM5402/ADuM5403/ADuM5404 Spacings
1k
supply current is equal to the sum of the quiescent
power supply input provides power to the iCoupler
DISTANCE = 100mm
10k
DISTANCE = 5mm
DD1(Q)
MAGNETIC FIELD FREQUENCY (Hz)
current, as shown in Figure 27. The
100k
ISO
1M
load.
DISTANCE = 1m
DD1(D)
10M
, demanded by
100M
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ADuM5401/ADuM5402/ADuM5403/ADuM5404
Dynamic I/O current is consumed only when operating a channel
at speeds higher than the refresh rate of f
of each channel is determined by its data rate. Figure 19 shows the
current for a channel in the forward direction, meaning that the
input is on the V
for a channel in the reverse direction, meaning that the input is on
the V
The following relationship allows the total I
calculated:
where:
I
I
Figure 19 or Figure 20, depending on channel direction.
I
E is the power supply efficiency at 100 mA load from Figure 11
at the V
The maximum external load can be calculated by subtracting
the dynamic output load from the maximum allowable load.
where:
I
side load.
I
available at V
I
or output channel, as shown in Figure 21 and Figure 22.
The preceding analysis assumes a 15 pF capacitive load on each
data output. If the capacitive load is larger than 15 pF, the additional
current must be included in the analysis of I
DD1
CHn
ISO
ISO(LOAD)
ISO(MAX)
ISO(D)n
is the current drawn by the secondary side external load.
is the total supply input current.
is the current drawn by a single channel determined from
I
I
ISO
DD1
ISO(LOAD)
I
I
is the dynamic load current drawn from V
DD1(Q)
DD1(D)
is the maximum external secondary side load current
ISO
side of the part. Both figures assume a typical 15 pF load.
is the current available to supply an external secondary
= (I
and V
ADuM5401/ADuM5402/ADuM5403/ADuM5404
ISO
= I
ISO
Figure 27. Power Consumption Within the
× V
.
CONVERTER
ISO(MAX)
DD1
DD1
PRIMARY
PRIMARY
I
DATA
DDP(D)
4CH
ISO
I/O
side of the part. Figure 20 shows the current
condition of interest.
)/(E × V
− Σ I
ISO(D)n
DD1
E
) + Σ I
; n = 1 to 4
CONVERTER
SECONDARY
SECONDARY
CHn
DATA
4CH
I/O
I
ISO(D)
r
DD1
; n = 1 to 4
. The dynamic current
DD1
current to be
and I
ISO
by an input
I
ISO(LOAD)
ISO
.
(2)
(1)