ADUM2201BRIZ Analog Devices Inc, ADUM2201BRIZ Datasheet - Page 16

• Manufacturer Part Number: ADUM2201BRIZ
• Description: 63T8602
• Manufacturer: Analog Devices Inc

Specifications of ADUM2201BRIZ

• No. Of Channels: 2
• Propagation Delay: 50ns
• Supply Current: 2.6mA
• Supply Voltage Range: 3V To 5.5V
• Digital Ic Case Style: SOIC
• No. Of Pins: 16
• Operating Temperature Range: -40°C To +105°C

ADuM2200/ADuM2201
APPLICATIONS INFORMATION
PCB LAYOUT
The ADuM220x digital isolator requires no external interface
circuitry for the logic interfaces. Power supply bypassing is
strongly recommended at the input and output supply pins (see
Figure 12). Bypass capacitors are most conveniently connected
between Pin 1 and Pin 3 for V
Pin 16 for V
and 0.1 μF. The total lead length between both ends of the
capacitor and the input power supply pin should not exceed
20 mm. Bypassing between Pin 3 and Pin 7 and between Pin 9
and Pin 14 should be considered unless the ground pair on each
package side are connected close to the package.
In applications involving high common-mode transients, care
should be taken to ensure that board coupling across the
isolation barrier is minimized. Furthermore, the board layout
should be designed such that any coupling that does occur
equally affects all pins on a given component side. Failure to
ensure this could cause voltage differentials between pins
exceeding the device’s Absolute Maximum Ratings, thereby
leading to latch-up or permanent damage.
PROPAGATION DELAY-RELATED PARAMETERS
Propagation delay is a parameter that describes the length of
time it takes for a logic signal to propagate through a compo-
nent. The propagation delay to a logic low output can differ
from the propagation delay to logic high.
Pulse width distortion is the maximum difference between
these two propagation delay values and is an indication of how
accurately the input signal’s timing is preserved.
Channel-to-channel matching refers to the maximum amount
the propagation delay differs among channels within a single
ADuM220x component.
Propagation delay skew refers to the maximum amount the
propagation delay differs among multiple ADuM220x
components operated under the same conditions.
INPUT (V
OUTPUT (V
Ix
)
Figure 12. Recommended Printed Circuit Board Layout
Ox
V
IA
)
GND
GND
DD2
V
/V
DD1
NC
V
NC
NC
OA
IB
Figure 13. Propagation Delay Parameters
. The capacitor value should be between 0.01 μF
1
1
t
PLH
DD1
and between Pin 14 and
t
PHL
50%
GND
NC
V
V
V
NC
NC
GND
DD2
OA
OB
50%
/V
2
2
IA
Rev. A | Page 16 of 20
DC CORRECTNESS AND MAGNETIC FIELD
IMMUNITY
Positive and negative logic transitions at the isolator input cause
narrow (~1 ns) pulses to be sent via the transformer to the
decoder. The decoder is bistable and is therefore either set or
reset by the pulses, indicating input logic transitions. In the
absence of logic transitions at the input for more than ~1 μs, a
periodic set of refresh pulses indicative of the correct input state
is sent to ensure dc correctness at the output. If the decoder
receives no internal pulses for more than approximately 5 μs,
the input side is assumed to be without power or nonfunctional;
in which case, the isolator output is forced to a default state (see
Table 11 and Table 12) by the watchdog timer circuit.
The limitation on the ADuM220x magnetic field immunity is
set by the condition in which induced voltage in the transformer
receiving coil is large enough to either falsely set or reset the
decoder. The following analysis defines the conditions under
which this can occur. The 3 V operating condition of the
ADuM220x is examined because it represents the most
susceptible mode of operation.
The pulses at the transformer output have an amplitude greater
than 1.0 V. The decoder has a sensing threshold at about 0.5 V,
therefore establishing a 0.5 V margin in which induced voltages
can be tolerated. The voltage induced across the receiving coil is
given by
where:
β is the magnetic flux density (gauss).
N is the number of turns in the receiving coil.
r
Given the geometry of the receiving coil in the ADuM220x 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 14.
n
is the radius of the n
V = (−dβ/dt)Σπr
0.001
0.01
Figure 14. Maximum Allowable External Magnetic Flux Density
100
0.1
10
1
1k
10k
MAGNETIC FIELD FREQUENCY (Hz)
n
2
th
; n = 1, 2,…, N
turn in the receiving coil (cm).
100k
1M
10M
100M