ADUM5242ARZ Analog Devices Inc, ADUM5242ARZ Datasheet - Page 12

• Manufacturer Part Number: ADUM5242ARZ
• Description: IC ISOLATOR 2CH W/CONV 8-SOIC
• Manufacturer: Analog Devices Inc
• Series: IsoPower®, iCoupler®r

Specifications of ADUM5242ARZ

• Propagation Delay: 70ns
• Inputs - Side 1/side 2: 0/2
• Number Of Channels: 2
• Isolation Rating: 2500Vrms
• Voltage - Supply: 3.35V, 4.1V, 5V
• Data Rate: 1Mbps
• Output Type: Logic
• Package / Case: 8-SOIC (3.9mm Width)
• Operating Temperature: -40°C ~ 105°C
• No. Of Channels: 2
• Supply Current: 140mA
• Supply Voltage Range: 2.7V To 4V, 4.5V To 5.5V
• Digital Ic Case Style: SOIC
• No. Of Pins: 8
• Operating Temperature Range: -40°C To
• Package: 8SOIC N
• Operating Temperature (min): -40C
• Operating Temperature Classification: Industrial
• Operating Temperature (max): 105C
• Package Type: SOIC N
• Rad Hardened: No
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

ADuM5240/ADuM5241/ADuM5242
Given the geometry of the receiving coil in the ADuM524x 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 13.
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
ADuM524x transformers. Figure 14 expresses these allowable
current magnitudes as a function of frequency for selected
distances. As shown in Figure 14, the ADuM524x is extremely
immune and can only be affected by extremely large currents
operated at high frequencies very close to the component. For
the 1 MHz example noted, one would have to place a 0.5 kA
current 5 mm away from the ADuM524x to affect the operation
of the component.
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
DISTANCE = 100mm
for Various Current-to-ADuM524x Spacings
Figure 14. Maximum Allowable Current
10k
DISTANCE = 5mm
10k
MAGNETIC FIELD FREQUENCY (Hz)
MAGNETIC FIELD FREQUENCY (Hz)
100k
100k
1M
1M
DISTANCE = 1m
10M
10M
100M
100M
Rev. A | Page 12 of 16
Note that at combinations of strong magnetic field and high
frequency, any loops formed by printed circuit board (PCB)
traces could induce error voltages sufficiently large enough to
trigger the thresholds of succeeding circuitry. Care should be
taken in the layout of such traces to avoid this possibility.
THERMAL ANALYSIS
Each ADuM524x component consists of two internal die,
attached to a split-paddle lead frame. For the purposes of
thermal analysis, it is treated as a thermal unit with the highest
junction temperature reflected in the θ
value of θ
mounted on a JEDEC standard 4-layer PCB with fine-width
traces in still air. Under normal operating conditions, the
ADuM524x operates at full load across the full temperature
range without derating the output current. For example, a part
with no external load drawing 80 mA and dissipating 400 mW
causes a 32°C temperature rise above ambient. It is normal for
these devices to run warm.
Following the recommendations in the PCB Layout section
decreases the thermal resistance to the PCB allowing increased
thermal margin at high ambient temperatures.
PCB LAYOUT
The ADuM524x requires no external circuitry for its logic
interfaces. Power supply bypassing is required at the input and
output supply pins (see Figure 15).
The power supply section of the ADuM524x uses a 300 MHz
oscillator frequency to pass power through its chip scale trans-
formers. In addition, the normal operation of the data section of
the iCoupler introduces switching transients, as described in the
DC Correctness and Magnetic Field Immunity section, on the
power supply pins (see Figure 11). Low inductance capacitors are
required to bypass noise generated at the switching frequency as
well as 1 ns pulses generated by the data transfer and dc refresh
circuitry. The total lead length between both ends of the capacitor
and the input power supply pin should not exceed 20 mm.
In cases where EMI emission is a concern, series inductance
may be added to critical power and ground traces. Discrete
inductors should be added to the line such that the high frequency
bypass capacitors are between the inductor and the ADuM524x
device pin. Inductance can be added in the form of discrete
inductors or ferrite beads added to both power and ground
traces. The recommended value corresponds to impedance
between 50 Ω and 100 Ω at approximately 300 MHz.
If the switching speed of the data outputs is causing
unacceptable EMI, capacitance to ground can be added at
output pins to slow the rise and fall time of the output. This
slew rate limits the output. Capacitance values depend on
application speed requirements.
JA
is based on measurements taken with the part
JA
from Table 2. The