adum5400 Analog Devices, Inc., adum5400 Datasheet - Page 16

• Manufacturer Part Number: adum5400
• Description: Quad-channel Isolator With Integrated Dc-to-dc Converter
• Manufacturer: Analog Devices, Inc.

ADuM5400
The preceding magnetic flux density values correspond to specific
current magnitudes at given distances from the ADuM5400
transformers. Figure 20 expresses these allowable current
magnitudes as a function
of frequency for selected distances. As shown in Figure 20,
the ADuM5400 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, a 0.5 kA current would
need to be placed 5 mm away from the ADuM5400 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
Figure 20. Maximum Allowable Current for Various Current-to- ADuM5400
0.01
DD1
100
I
I
DD1
0.1
DD1(Q)
DD1(D)
1k
10
1
1k
supply current is equal to the sum of the quiescent
power supply input provides power to the iCoupler
Figure 21. Power Consumption Within the ADuM5400
DISTANCE = 100mm
CONVERTER
PRIMARY
PRIMARY
I
DATA
DDP(D)
DISTANCE = 5mm
10k
4CH
I/O
DD1(Q)
MAGNETIC FIELD FREQUENCY (Hz)
current, as shown in Figure 21. The
100k
Spacings
E
ISO
CONVERTER
SECONDARY
SECONDARY
1M
load.
DATA
4CH
DISTANCE = 1m
I/O
I
ISO(D)
DD1(D)
10M
, demanded by
I
ISO
100M
Rev. PrA | Page 16 of 21
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 13 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 13 or Figure 14, depending on channel direction.
I
E is the power supply efficiency at 100 mA load from Figure 5
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 15 and Figure 16.
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 current drawn by a single channel determined from
is the total supply input current.
I
I
ISO
DD1
ISO(LOAD)
is the dynamic load current drawn from V
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
ISO
= I
ISO
× V
.
ISO(MAX)
DD1
DD1
ISO
side of the part. Figure 14 shows the current
Preliminary Technical Data
condition of interest.
)/(E × V
− Σ I
ISO(D)n
DD1
) + Σ I
; n = 1 to 4
CHn
r
; n = 1 to 4
DD1
. The dynamic current
DD1
current to be
and I
ISO
by an input
ISO(LOAD)
.
(2)
(1)