ADUM5401_VB AD [Analog Devices], ADUM5401_VB Datasheet - Page 22

• Manufacturer Part Number: ADUM5401_VB
• Description: Quad-Channel, 2.5 kV Isolators with Integrated DC-to-DC Converter
• Manufacturer: AD [Analog Devices]

ADuM5401/ADuM5402/ADuM5403/ADuM5404
Given the geometry of the receiving coil in the ADuM5401/
ADuM5402/ADuM5403/ADuM5404, and an imposed
requirement that the induced voltage be, at most, 50% of the
0.5 V margin at the decoder, a maximum allowable magnetic
field is calculated as shown in Figure 27.
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 voltage is approximately 50% of the sensing
threshold and does not cause a faulty output transition. Similarly, if
such an event occurs during a transmitted pulse (and is of the
worst-case polarity), it reduces 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 ADuM5401/
ADuM5402/ADuM5403/ADuM5404
expresses these allowable current magnitudes as a function of
frequency for selected distances. As shown in Figure 28, the
ADuM5401/ADuM5402/ADuM5403/ADuM5404
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 placed 5 mm away from the
ADuM5401/ADuM5402/ADuM5403/ADuM5404
affect the operation of the device.
0.001
0.01
0.01
Figure 27. Maximum Allowable External Magnetic Flux Density
Figure 28. Maximum Allowable Current for Various Current-to-
100
100
0.1
0.1
1k
10
10
1
1
ADuM5401/ADuM5402/ADuM5403/ADuM5404 Spacings
1k
1k
DISTANCE = 100mm
10k
10k
DISTANCE = 5mm
MAGNETIC FIELD FREQUENCY (Hz)
MAGNETIC FIELD FREQUENCY (Hz)
100k
100k
1M
1M
transformers. Figure 28
DISTANCE = 1m
10M
10M
are extremely
is required to
100M
100M
Rev. B | Page 22 of 28
Note that, at combinations of strong magnetic field and high
frequency, any loops formed by PCB traces can induce error
voltages sufficiently large to trigger the thresholds of succeeding
circuitry. Exercise care in the layout of such traces to avoid this
possibility.
POWER CONSUMPTION
The V
channels, as well as to the power converter. For this reason, the
quiescent currents drawn by the data converter and the primary
and secondary input/output channels cannot be determined
separately. All of these quiescent power demands have been
combined into the I
total I
current; the dynamic current, I
channels; and any external I
Both dynamic input and output current is consumed only
when operating at channel speeds higher than the refresh rate,
f
rate. Figure 21 shows the current for a channel in the forward
direction, which means that the input is on the primary side of
the part. Figure 22 shows the current for a channel in the reverse
direction, which means that the input is on the secondary side of
the part. Both figures assume a typical 15 pF load. The following
relationship allows the total I
where:
I
I
Figure 21 or Figure 22, depending on channel direction.
I
E is the power supply efficiency at 100 mA load from Figure 11
at the V
r
DD1
CHn
ISO
. Each channel has a dynamic current determined by its data
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
DD1
DD1
DD1
I
I
DD1(Q)
DD1(D)
ISO
= (I
power supply input provides power to the iCoupler data
supply current is the sum of the quiescent operating
and V
ADuM5401/ADuM5402/ADuM5403/ADuM5404
ISO
Figure 29. Power Consumption Within the
INPUT/OUTPUT
× V
CONVERTER
4-CHANNEL
DD1
PRIMARY
PRIMARY
I
DATA
DDP(D)
ISO
DD1 (Q)
condition of interest.
)/(E × V
current, as shown in Figure 29. The
DD1
ISO
DD1
current to be calculated:
load.
DD1 (D)
) + Σ I
INPUT/OUTPUT
CONVERTER
SECONDARY
SECONDARY
, demanded by the I/O
4-CHANNEL
CHn
DATA
I
ISO(D)
; n = 1 to 4
Data Sheet
I
ISO
(1)