Hot Swappable, Dual I2C Isolators, 5 kV
ADuM2250/ADuM2251
Data Sheet
FEATURES
GENERAL DESCRIPTION
Bidirectional I2C communication
Open-drain interfaces
Suitable for hot swap applications
30 mA current sink capability
1000 kHz operation
3.0 V to 5.5 V supply/logic levels
16-lead SOIC wide body package version (RW-16)
16-lead SOIC wide body enhanced creepage version (RI-16-2)
High temperature operation: 105°C
Safety and regulatory approvals
UL recognition: 5000 V rms for 1 minute per UL 1577
CSA Component Acceptance Notice 5A (RI-16-2 package)
IEC 60601-1: 250 V rms (reinforced)
IEC 60950-1: 400 V rms (reinforced)
VDE certificate of conformity
DIN V VDE V 0884-10 (VDE V 0884-10):2006-12
VIORM = 849 V peak
Qualified for automotive applications
The ADuM2250/ADuM22511 are hot swappable digital isolators
with nonlatching, bidirectional communication channels that
are compatible with I2C interfaces. This eliminates the need for
splitting I2C signals into separate transmit and receive signals for
use with standalone optocouplers.
APPLICATIONS
Isolated I2C, SMBus, or PMBus interfaces
Multilevel I2C interfaces
Power supplies
Networking
Power over Ethernet
The ADuM2250 provides two bidirectional channels, supporting
a complete isolated I2C interface. The ADuM2251 provides one
bidirectional channel and one unidirectional channel for those
applications where a bidirectional clock is not required.
The ADuM2250/ADuM2251 contain hot swap circuitry to
prevent data glitches when an unpowered card is inserted onto
an active bus.
These isolators are based on iCoupler® chip scale transformer
technology from Analog Devices, Inc. iCoupler is a magnetic
isolation technology with performance, size, power consumption, and functional advantages compared to optocouplers. The
ADuM2250/ADuM2251 integrate iCoupler channels with semiconductor circuitry to enable a complete, isolated I2C interface
in a small form factor package.
FUNCTIONAL BLOCK DIAGRAMS
NC 2
15 NC
VDD1 3
NC 2
14 VDD2
NC 4
DECODE
ENCODE
13 NC
SDA1 5
ENCODE
DECODE
12 SDA2
SCL1 6
DECODE
ENCODE
11 SCL2
GND1 7
ENCODE
DECODE
10 NC
NC 8
9
NC = NO CONNECT
GND2
15 NC
VDD1 3
14 VDD2
NC 4
DECODE
ENCODE
13 NC
SDA1 5
ENCODE
DECODE
12 SDA2
SCL1 6
ENCODE
DECODE
11 SCL2
GND1 7
Figure 1. ADuM2250 Functional Block Diagram
1
16 GND2
ADuM2251
10 NC
NC 8
9
NC = NO CONNECT
GND2
06670-002
GND1 1
16 GND2
ADuM2250
06670-001
GND1 1
Figure 2. ADuM2251 Functional Block Diagram
Protected by U.S. Patents 5,952,849; 6,873,065; and 7,075,329; other patents pending.
Rev. D
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ADuM2250/ADuM2251
Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1
Absolute Maximum Ratings ............................................................7
Applications ....................................................................................... 1
ESD Caution...................................................................................7
General Description ......................................................................... 1
Pin Configuration and Function Descriptions..............................8
Functional Block Diagrams ............................................................. 1
Test Conditions ..................................................................................9
Revision History ............................................................................... 2
Applications Information .............................................................. 10
Specifications..................................................................................... 3
Functional Description .............................................................. 10
Electrical Characteristics ............................................................. 3
Startup .......................................................................................... 11
Package Characteristics ............................................................... 5
Capacitive Load at Low Speeds ................................................ 11
Regulatory Information ............................................................... 5
Magnetic Field Immunity.......................................................... 12
Insulation and Safety Related Specifications ............................ 5
Outline Dimensions ....................................................................... 13
DIN V VDE V 0884-10 (VDE V 0884-10):2006-12 Insulation
Characteristics ................................................................................ 6
Ordering Guide .......................................................................... 14
Automotive Products ................................................................. 14
Recommended Operating Conditions ...................................... 6
REVISION HISTORY
7/15—Rev. C to Rev. D
Changes to Table 4 and Table 5 ....................................................... 5
Changes to Ordering Guide .......................................................... 14
4/14—Rev. B to Rev. C
Changes to Features Section............................................................ 1
Added Capacitive Load at Low Speeds Section .......................... 11
Changes to Ordering Guide .......................................................... 14
Added Automotive Products Section .......................................... 14
9/11—Rev. 0 to Rev. A
Added 16-Lead SOIC ......................................................... Universal
Changes to Features Section and Endnote 1 ..................................1
Changes to Table 4 and Table 5 .......................................................6
Changes to Endnote 1 in Table 7 .....................................................7
Changes to Functional Description Section and Figure 7 ........ 10
Updated Outline Dimensions ....................................................... 13
Changes to Ordering Guide .......................................................... 13
4/07—Revision 0: Initial Version
3/13—Rev. A to Rev. B
Created Hyperlink for Safety and Regulatory Approvals
Entry in Features Section................................................................. 1
Changes to Features Section............................................................ 1
Changes to Table 4 ............................................................................ 5
Changes to DIN V VDE V 0884-10
(VDE V 0884-10):2006-12 Section and Table 6 ........................... 6
Reformatted Table 8 ......................................................................... 7
Changes to Figure 4, Table 9, and Table 10 ................................... 8
Moved Test Conditions Section ...................................................... 9
Changes to Functional Description Section ............................... 10
Changes to Captions of Figure 8 and Figure 9 ............................ 11
Rev. D | Page 2 of 16
Data Sheet
ADuM2250/ADuM2251
SPECIFICATIONS
ELECTRICAL CHARACTERISTICS
DC Specifications
All voltages are relative to their respective grounds. All minimum/maximum specifications apply over the entire recommended operating
range, unless otherwise noted. All typical specifications are at TA = 25°C, VDD1 = 5 V, and VDD2 = 5 V, unless otherwise noted.
Table 1.
Parameter
Symbol
Min
Typ
Max
Unit
Test Conditions/Comments
IDD1
IDD2
IDD1
IDD2
2.8
2.7
1.9
1.7
5.0
5.0
3.0
3.0
mA
mA
mA
mA
VDD1 = 5 V
VDD2 = 5 V
VDD1 = 3.3 V
VDD2 = 3.3 V
IDD1
IDD2
IDD1
IDD2
IISDA1, IISDA2,
IISCL1, IISCL2
2.8
2.5
1.8
1.6
0.01
6.0
4.7
3.0
2.8
10
mA
mA
mA
mA
µA
VDD1 = 5 V
VDD2 = 5 V
VDD1 = 3.3 V
VDD2 = 3.3 V
VSDA1 = VDD1, VSDA2 = VDD2,
VSCL1 = VDD1, VSCL2 = VDD2
700
900
850
mV
mV
mV
mV
0.3 × VDD2
V
V
mV
ADuM2250
Input Supply Current, Side 1, 5 V
Input Supply Current, Side 2, 5 V
Input Supply Current, Side 1, 3.3 V
Input Supply Current, Side 2, 3.3 V
ADuM2251
Input Supply Current, Side 1, 5 V
Input Supply Current, Side 2, 5 V
Input Supply Current, Side 1, 3.3 V
Input Supply Current, Side 2, 3.3 V
LEAKAGE CURRENTS
SIDE 1 LOGIC LEVELS
Logic Input Threshold 1
Logic Low Output Voltage
Input/Output Logic Low Level Difference 2
SIDE 2 LOGIC LEVELS
Logic Low Input Voltage
Logic High Input Voltage
Logic Low Output Voltage
1
2
VSDA1IL, VSCL1IL
VSDA1OL, VSCL1OL
ΔVSDA1, ΔVSCL1
VSDA2IL, VSCL2IL
VSDA2IH, VSCL2IH
VSDA2OL, VSCL2OL
500
600
600
50
0.7 × VDD2
400
ISDA1 = ISCL1 = 3.0 mA
ISDA1 = ISCL1 = 0.5 mA
ISDA2 = ISCL2 = 30 mA
VIL < 0.5 V, VIH > 0.7 V.
ΔVS1 = VS1OL − VS1IL. This is the minimum difference between the output logic low level and the input logic low threshold within a given component. This ensures that
there is no possibility of the part latching up the bus to which it is connected.
Rev. D | Page 3 of 16
ADuM2250/ADuM2251
Data Sheet
AC Specifications
All voltages are relative to their respective grounds. All minimum/maximum specifications apply over the entire recommended operating
range, unless otherwise noted. All typical specifications are at TA = 25°C, VDD1 = 5 V, and VDD2 = 5 V, unless otherwise noted. See Figure 5
for a timing test diagram.
Table 2.
Parameter
MAXIMUM FREQUENCY
OUTPUT FALL TIME
5 V Operation
Symbol
tf1
tf2
Side 1 Output (0.9 VDD1 to 0.9 V)
Side 2 Output (0.9 VDD2 to 0.1 VDD2)
PROPAGATION DELAY
5 V Operation
tf1
tf2
Max
Unit
kHz
Test Conditions/Comments
13
32
26
52
120
120
ns
ns
3.0 V ≤ VDD1, VDD2 ≤ 3.6 V, CL1 = 40 pF,
R1 = 1.0 kΩ, CL2 = 400 pF, R2 = 120 Ω
13
32
32
61
120
120
ns
ns
4.5 V ≤ VDD1, VDD2 ≤ 5.5 V, CL1 = CL2 = 0 pF,
R1 = 1.6 kΩ, R2 = 180 Ω
Side 1 to Side 2, Rising Edge 1
Side 1 to Side 2, Falling Edge 2
Side 2 to Side 1, Rising Edge 3
Side 2 to Side 1, Falling Edge 4
3 V Operation
tPLH12
tPHL12
tPLH21
tPHL21
Side 1 to Side 2, Rising Edge1
Side 1 to Side 2, Falling Edge2
Side 2 to Side 1, Rising Edge3
Side 2 to Side 1, Falling Edge4
PULSE WIDTH DISTORTION
5 V Operation
tPLH12
tPHL12
tPLH21
tPHL21
Side 1 to Side 2, |tPLH12 − tPHL12|
Side 2 to Side 1, |tPLH21 − tPHL21|
COMMON-MODE TRANSIENT IMMUNITY 5
Typ
4.5 V ≤ VDD1, VDD2 ≤ 5.5 V, CL1 = 40 pF,
R1 = 1.6 kΩ, CL2 = 400 pF, R2 = 180 Ω
Side 1 Output (0.9 VDD1 to 0.9 V)
Side 2 Output (0.9 VDD2 to 0.1 VDD2)
3 V Operation
Side 1 to Side 2, |tPLH12 − tPHL12|
Side 2 to Side 1, |tPLH21 − tPHL21|
3 V Operation
Min
1000
95
162
31
85
130
275
70
155
ns
ns
ns
ns
3.0 V ≤ VDD1, VDD2 ≤ 3.6 V, CL1 = CL2 = 0 pF,
R1 = 1.0 kΩ, R2 = 120 Ω
82
196
32
110
125
340
75
210
ns
ns
ns
ns
4.5 V ≤ VDD1, VDD2 ≤ 5.5 V, CL1 = CL2 = 0 pF,
R1 = 1.6 kΩ, R2 = 180 Ω
PWD12
PWD21
67
54
145
85
ns
ns
3.0 V ≤ VDD1, VDD2 ≤ 3.6 V, CL1 = CL2 = 0 pF,
R1 = 1.0 kΩ, R2 = 120 Ω
PWD12
PWD21
|CMH|, |CML|
25
114
77
35
215
135
ns
ns
kV/µs
tPLH12 propagation delay is measured from the Side 1 input logic threshold to an output value of 0.7 VDD2.
tPHL12 propagation delay is measured from the Side 1 input logic threshold to an output value of 0.4 V.
3
tPLH21 propagation delay is measured from the Side 2 input logic threshold to an output value of 0.7 VDD1.
4
tPHL21 propagation delay is measured from the Side 2 input logic threshold to an output value of 0.9 V.
5
CMH is the maximum common-mode voltage slew rate that can be sustained while maintaining VO > 0.8 VDD2. CML is the maximum common-mode voltage slew rate
that can be sustained while maintaining VO < 0.8 V. The common-mode voltage slew rates apply to both rising and falling common-mode voltage edges. The transient
magnitude is the range over which the common mode is slewed.
1
2
Rev. D | Page 4 of 16
Data Sheet
ADuM2250/ADuM2251
PACKAGE CHARACTERISTICS
Table 3.
Parameter
Resistance (Input to Output)1
Capacitance (Input to Output)1
Input Capacitance
IC Junction to Ambient Thermal Resistance
1
Symbol
RI-O
CI-O
CI
θJA
Min
Typ
1012
2.2
4.0
45
Max
Unit
Ω
pF
pF
°C/W
Test Conditions/Comments
f = 1 MHz
Thermocouple located at center of
package underside
The device is considered a 2-terminal device; Pin 1 through Pin 8 are shorted together, and Pin 9 through Pin 16 are shorted together.
REGULATORY INFORMATION
The ADuM2250/ADuM2251 are approved by the organizations listed in Table 4.
Table 4.
UL
Recognized Under
UL 1577 Component
Recognition Program1
Single Protection,
5000 V rms Isolation
Voltage
File E214100
1
2
CSA
Approved under CSA Component
Acceptance Notice 5A
CQC
Approved under CQC11-471543-2012
Basic insulation per CSA 60950-1-07
and IEC 60950-1, 600 V rms
(849 V peak) maximum
working voltage
RW-16 package: reinforced
insulation per CSA 60950-1-07 and
IEC 60950-1, 380 V rms (537 V peak)
maximum working voltage
Reinforced insulation per
IEC 60601-1, 125 V rms (176 V peak)
maximum working voltage
RI-16-2 package: reinforced
insulation per CSA 60950-1-07 and
IEC 60950-1, 400 V rms (565 V peak)
maximum working voltage
Reinforced insulation per
IEC 60601-1, 250 V rms (353 V peak)
maximum working voltage
File 205078
Basic insulation per GB4943.1-2011,
600 V rms (848 V peak) maximum
working voltage, tropical climate,
altitude ≤ 5000 m
RW-16 package: reinforced insulation
per GB4943.1-2011, 380 V rms (537 V peak)
maximum working voltage,
tropical climate, altitude ≤ 5000 m
VDE
Certified according to
DIN V VDE V 0884-10
(VDE V 0884-10):2006-122
Reinforced insulation,
849 V peak
RI-16 package: reinforced insulation
per 400 V rms (565 V peak) maximum
working voltage, tropical climate,
altitude ≤ 5000 m
File CQC14001117251
File 2471900-4880-0001
In accordance with UL 1577, each ADuM2250/ADuM2251 is proof tested by applying an insulation test voltage ≥ 6000 V rms for 1 sec (current leakage detection limit = 10 μA).
In accordance with DIN V VDE V 0884-10 (VDE V 0884-10):2006-12, each ADuM2250/ADuM2251 is proof tested by applying an insulation test voltage ≥ 1590 V peak for 1 sec
(partial discharge detection limit = 5 pC). The asterisk (*) marking branded on the component designates DIN V VDE V 0884-10 (VDE V 0884-10):2006-12 approval.
INSULATION AND SAFETY RELATED SPECIFICATIONS
Table 5.
Parameter
Rated Dielectric Insulation Voltage
Minimum External Air Gap (Clearance)
Symbol
Minimum External Tracking (Creepage)
L(I02)
RW-16 Package
RI-16-2 Package
Minimum Internal Distance (Internal Clearance)
Tracking Resistance (Comparative Tracking Index)
Isolation Group
L(I01)
CTI
Value
5000
8.0 min
Unit
V rms
mm
7.7 min
8.3 min
0.017 min
>400
II
mm
mm
mm
V
Rev. D | Page 5 of 16
Test Conditions/Comments
1-minute duration
Distance measured from input terminals to output
terminals, shortest distance through air along the
PCB mounting plane, as an aid to PC board layout
Measured from input terminals to output
terminals, shortest distance path along body
Insulation distance through insulation
DIN IEC 112/VDE 0303, Part 1
Material Group (DIN VDE 0110, 1/89, Table 1)
ADuM2250/ADuM2251
Data Sheet
DIN V VDE V 0884-10 (VDE V 0884-10):2006-12 INSULATION CHARACTERISTICS
These isolators are suitable for reinforced isolation only within the safety limit data. Maintenance of the safety data is ensured by protective
circuits. The asterisk (*) marking branded on the component designates DIN V VDE V 0884-10 (VDE V 0884-10):2006-12 approval for
an 849 V peak working voltage.
Table 6.
Description
Installation Classification per DIN VDE 0110
For Rated Mains Voltage ≤ 300 V rms
For Rated Mains Voltage ≤ 450 V rms
For Rated Mains Voltage ≤ 600 V rms
Climatic Classification
Pollution Degree per DIN VDE 0110, Table 1
Maximum Working Insulation Voltage
Input to Output Test Voltage, Method b1
Input to Output Test Voltage, Method a
After Environmental Tests Subgroup 1
After Input and/or Safety Tests
Subgroup 2 and Subgroup 3
Highest Allowable Overvoltage
Safety Limiting Values
Case Temperature
Supply Current
Insulation Resistance at TS
Test Conditions/Comments
VIORM × 1.875 = VPR, 100% production test, tm = 1 sec,
partial discharge < 5 pC
Unit
VIORM
VPR
I to IV
I to II
I to II
40/105/21
2
849
1592
V peak
V peak
1358
1018
V peak
V peak
VTR
6000
V peak
TS
IS
RS
150
555
>109
°C
mA
Ω
VPR
Transient overvoltage, tTR = 10 sec
Maximum value allowed in the event of a failure
(see Figure 3)
IDD1 + IDD2
VIO = 500 V
RECOMMENDED OPERATING CONDITIONS
600
Table 7.
Parameter
Operating Temperature
Supply Voltages 1
Input/Output Signal
Voltage
Capacitive Load
Side 1
Side 2
Static Output Loading
Side 1
Side 2
500
400
300
200
100
0
50
100
150
AMBIENT TEMPERATURE (°C)
200
06670-003
SAFE OPERATING VDD1 CURRENT (mA)
Characteristic
VIORM × 1.6 = VPR, tm = 60 sec, partial discharge < 5 pC
VIORM × 1.2 = VPR, tm = 60 sec, partial discharge < 5 pC
Thermal Derating Curve
0
Symbol
1
Symbol
TA
VDD1, VDD2
VSDA1, VSCL1,
VSDA2, VSCL2
Min
−40
3.0
CL1
CL2
ISDA1, ISCL1
ISDA2, ISCL2
0.5
0.5
All voltages are relative to their respective grounds.
Figure 3. Thermal Derating Curve, Dependence of Safety Limiting Values
on Case Temperature, per DIN V VDE V 0884-10
Rev. D | Page 6 of 16
Max
+105
5.5
5.5
Unit
°C
V
V
40
400
pF
pF
3
30
mA
mA
Data Sheet
ADuM2250/ADuM2251
ABSOLUTE MAXIMUM RATINGS
TA = 25°C, unless otherwise noted.
Stresses at or above those listed under Absolute Maximum
Ratings may cause permanent damage to the product. This is a
stress rating only; functional operation of the product at these
or any other conditions above those indicated in the operational
section of this specification is not implied. Operation beyond
the maximum operating conditions for extended periods may
affect product reliability.
Table 8.
Parameter
Storage Temperature (TST)
Ambient Operating Temperature (TA)
Supply Voltages (VDD1, VDD2) 1
Input/Output Voltage
Side 1 (VSDA1, VSCL1)1
Side 2 (VSDA2, VSCL2)1
Average Output Current per Pin 2
Side 1 (IO1)
Side 2 (IO2)
Common-Mode Transients 3
Rating
−65°C to +150°C
−40°C to +105°C
−0.5 V to +7.0 V
ESD CAUTION
−0.5 V to VDD1 + 0.5 V
−0.5 V to VDD2 + 0.5 V
±18 mA
±100 mA
−100 kV/µs to +100 kV/µs
All voltages are relative to their respective grounds.
See Figure 3 for maximum rated current values for various temperatures.
3
Refers to common-mode transients across the insulation barrier. Commonmode transients exceeding the absolute maximum rating may cause latch-up
or permanent damage.
1
2
Rev. D | Page 7 of 16
ADuM2250/ADuM2251
Data Sheet
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
16 GND2
GND1 1
15 NC
NC 2
VDD1 3
NC 4
SDA1 5
SCL1 6
GND1
7
ADuM2250/
ADuM2251
TOP VIEW
(Not to Scale)
14 VDD2
13 NC
12 SDA2
11 SCL2
10 NC
NC 8
9
GND2
06670-004
NC = NO CONNECT
NOTES
1. PIN 1 AND PIN 7 ARE INTERNALLY CONNECTED TO EACH OTHER, AND IT IS
RECOMMENDED THAT BOTH PINS BE CONNECTED TO A COMMON GROUND.
2. PIN 9 AND PIN 16 ARE INTERNALLY CONNECTED TO EACH OTHER, AND IT IS
RECOMMENDED THAT BOTH PINS BE CONNECTED TO A COMMON GROUND.
Figure 4. Pin Configuration
Table 9. ADuM2250 Pin Function Descriptions
Pin No.
1, 7
Mnemonic
GND1
2, 4, 8, 10,
13, 15
3
5
6
9, 16
NC
11
12
14
SCL2
SDA2
VDD2
VDD1
SDA1
SCL1
GND2
Description
Ground 1. Ground reference for Isolator Side 1. Pin 1 and Pin 7 are internally connected to each other, and
it is recommended that both pins be connected to a common ground.
No Connect.
Supply Voltage, 3.0 V to 5.5 V.
Data Input/Output, Side 1.
Clock Input/Output, Side 1.
Ground 2. Isolated ground reference for Isolator Side 2. Pin 9 and Pin 16 are internally connected to each
other, and it is recommended that both pins be connected to a common ground.
Clock Input/Output, Side 2.
Data Input/Output, Side 2.
Supply Voltage, 3.0 V to 5.5 V.
Table 10. ADuM2251 Pin Function Descriptions
Pin No.
1, 7
Mnemonic
GND1
2, 4, 8, 10,
13, 15
3
5
6
9, 16
NC
11
12
14
SCL2
SDA2
VDD2
VDD1
SDA1
SCL1
GND2
Description
Ground 1. Ground reference for Isolator Side 1. Pin 1 and Pin 7 are internally connected to each other, and
it is recommended that both pins be connected to a common ground.
No Connect.
Supply Voltage, 3.0 V to 5.5 V.
Data Input/Output, Side 1.
Clock Input, Side 1.
Ground 2. Isolated ground reference for Isolator Side 2. Pin 9 and Pin 16 are internally connected to each
other, and it is recommended that both pins be connected to a common ground.
Clock Output, Side 2.
Data Input/Output, Side 2.
Supply Voltage, 3.0 V to 5.5 V.
Rev. D | Page 8 of 16
Data Sheet
ADuM2250/ADuM2251
TEST CONDITIONS
NC
VDD1
R1
R1
NC
SDA1
SCL1
CL1
CL1
GND1
NC
16
1
2
ADuM2250
15
14
3
4
DECODE
ENCODE
13
5
ENCODE
DECODE
12
6
DECODE
ENCODE
11
7
ENCODE
DECODE
10
9
8
NC = NO CONNECT
Figure 5. Timing Test Diagram
Rev. D | Page 9 of 16
GND2
NC
VDD2
NC
R2
R2
CL2
CL2
SDA2
SCL2
NC
GND2
06670-005
GND1
ADuM2250/ADuM2251
Data Sheet
APPLICATIONS INFORMATION
The ADuM2250/ADuM2251 interface on each side to I C signals. Internally, the bidirectional I2C signals are split into two
unidirectional channels communicating in opposite directions
via dedicated iCoupler isolation channels. One channel of each
pair (the Side 1 input of each input/output pin in Figure 6)
implements a special input buffer and output driver that can
differentiate between externally generated inputs and its own
output signals. It transfers only externally generated input
signals to the corresponding Side 2 data or clock pin.
Both the Side 1 and Side 2 I2C pins are designed to interface to
an I2C bus operating in the 3.0 V to 5.5 V range. A logic low on
either side causes the corresponding input/output pin across the
coupler to be pulled low enough to comply with the logic low
threshold requirements of other I2C devices on the bus. Bus
contention and latch-up are avoided by guaranteeing that the
input low threshold at SDA1 or SCL1 is at least 50 mV less than
the output low signal at the same pin. This prevents an output
logic low at Side 1 from being transmitted back to Side 2 and
pulling down the I2C bus by latching the state.
Because the Side 2 logic levels/thresholds and drive capabilities
comply fully with standard I2C values, multiple ADuM2250/
ADuM2251 devices connected to a bus by their Side 2 pins can
communicate with each other and with other I2C-compatible
devices, as shown in Figure 7. Note the distinction between I2C
compatibility and I2C compliance. I2C compatibility refers to situations in which the logic levels or drive capability of a component
do not necessarily meet the requirements of the I2C specification
but still allow the component to communicate with an I2C-compliant device. I2C compliance refers to situations in which the
logic levels and drive capability of a component fully meet the
requirements of the I2C specification.
Because the Side 1 pin has a modified output level/input threshold,
Side 1 of the ADuM2250/ADuM2251 can communicate only with
devices that are fully compliant with the I2C standard. In other
words, Side 2 of the ADuM2250/ADuM2251 is I2C-compliant,
whereas Side 1 is only I2C-compatible.
The Side 1 input/output pins must not be connected to other
I2C buffers that implement a similar scheme of dual input/output
threshold detection. This latch-up prevention scheme is
implemented in several popular I2C level shifting and bus
extension products currently available from Analog Devices
and other manufacturers. Care should be taken to review the
data sheet of potential I2C bus buffering products to ensure that
only one buffer on a bus segment implements a dual threshold
scheme.
A bus segment is a portion of the I2C bus that is isolated from
other portions of the bus by galvanic isolation, bus extenders, or
level shifting buffers. Table 11 shows how multiple ADuM2250/
ADuM2251 components can coexist on a bus as long as two
Side 1 buffers are not connected to the same bus segment.
Table 11. ADuM2250/ADuM2251 Buffer Compatibility
Side 1
No
Yes
Side 1
Side 2
Side 2
Yes
Yes
The output logic low levels are independent of the VDD1 and
VDD2 voltages. The input logic low threshold at Side 1 is also
independent of VDD1. However, the input logic low threshold at
Side 2 is designed to be at 0.3 VDD2, consistent with I2C requirements. The Side 1 and Side 2 input/output pins have opencollector outputs whose high levels are set via pull-up resistors
to their respective supply voltages.
GND1
NC
VDD1
NC
SDA1
SCL1
GND1
NC
1
2
16
ADuM2250
15
14
3
4
DECODE
ENCODE
13
5
ENCODE
DECODE
12
6
DECODE
ENCODE
11
7
ENCODE
DECODE
10
8
9
GND2
NC
VDD2
NC
SDA2
SCL2
NC
GND2
SYMBOL INDICATES A DUAL THRESHOLD INPUT BUFFER.
NC = NO CONNECT
Figure 6. ADuM2250 Block Diagram
Figure 7 shows a typical application circuit, including the pull-up
resistors required for both Side 1 and Side 2 buses. Bypass capacitors with values from 0.01 μF to 0.1 μF are required between
VDD1 and GND1 and between VDD2 and GND2. The 200 Ω resistor
shown in Figure 7 is required for latch-up immunity if the ambient
temperature can be between 105°C and 125°C.
I2C BUS
1
MICROPROCESSOR
OR
SECONDARY
BUS
SEGMENT
OPTIONAL
200Ω
VDD1
SDA1
SCL 1
GND1
2
16
ADuM2250
15
3
14
4
13
5
12
6
11
7
10
8
9
VDD2
SDA2
SCL2
GND2
Figure 7. Typical Isolated I2C Interface Using the ADuM2250
Rev. D | Page 10 of 16
06670-007
2
06670-006
FUNCTIONAL DESCRIPTION
Data Sheet
ADuM2250/ADuM2251
STARTUP
MINIMUM RECOMMENDED
OPERATING SUPPLY, 3.0V
INTERNAL START-UP
THRESHOLD, 2.0V
For the signal channels to be enabled, the following criteria
must be met:
•
•
Both supplies must be at least 2.5 V.
At least 40 μs must elapse after both supplies exceed the
internal start-up threshold of 2.0 V.
40µs
Figure 9. Start-Up Condition, Supply Slew Rate < 12.5 V/ms
CAPACITIVE LOAD AT LOW SPEEDS
Until both criteria are met for both supplies, the ADuM2250/
ADuM2251 outputs are pulled high, thereby ensuring a startup
that avoids any disturbances on the bus. Figure 8 and Figure 9
illustrate the supply conditions for fast and slow input supply
slew rates.
MINIMUM RECOMMENDED
OPERATING SUPPLY, 3.0V
SUPPLY VALID
MINIMUM VALID SUPPLY, 2.5V
40µs
The ADuM2250/ADuM2251 are designed for operation at
speeds up to 1 Mbps. Due to the limited current available on
Side 1 operation at 1 Mbps limits the capacitance that can be
driven at the minimum pull-up value to 40 pF.
Most applications operate at 100 kbps in standard mode or
400 kbps in fast mode. At these lower operating speeds, the
limitation on the load capacitance can be significantly relaxed.
Table 12 shows the maximum capacitance at minimum pull-up
values for standard and fast operating modes. If larger values for
the pull-up resistor are used, the maximum supported capacitance
must be scaled down proportionately so that the rise time does
not increase beyond the values required by the standard.
06670-008
INTERNAL START-UP
THRESHOLD, 2.0V
SUPPLY VALID
MINIMUM VALID SUPPLY, 2.5V
06670-009
Both the VDD1 and VDD2 supplies have an undervoltage lockout
feature that prevents the signal channels from operating unless
certain criteria are met. This feature prevents the possibility of
input logic low signals pulling down the I2C bus inadvertently
during power-up/power-down.
Figure 8. Start-Up Condition, Supply Slew Rate > 12.5 V/ms
Table 12. Side 1 Maximum Load Conditions
Mode
Standard
Fast
Standard
Fast
VDD1
5
5
3.3
3.3
Data Rate (kbps)
100
400
100
400
Maximum Capacitive Load for Side 1
tr (ns)
tf (ns)
1000
187
300
172
1000
270
300
235
Rev. D | Page 11 of 16
R1 (Ω)
1600
1600
1000
1000
CL1 (pF)
484
120
771
188
ADuM2250/ADuM2251
Data Sheet
The pulses at the transformer output have an amplitude greater
than 1.0 V. The decoder has a sensing threshold at approximately
0.5 V, thus establishing a 0.5 V margin in which induced voltages
can be tolerated. The voltage induced across the receiving coil is
given by
V = (−dβ/dt) ∑ πrn2; n = 1, 2, … , N
where:
β is the magnetic flux density (gauss).
rn is the radius of the nth turn in the receiving coil (cm).
N is the number of turns in the receiving coil.
Given the geometry of the receiving coil in the ADuM2250/
ADuM2251 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 10.
MAXIMUM ALLOWABLE MAGNETIC FLUX
DENSITY (kgauss)
100
10
1
0.1
The preceding magnetic flux density values correspond to
specific current magnitudes at given distances away from the
ADuM2250/ADuM2251 transformers. Figure 11 expresses
these allowable current magnitudes as a function of frequency
for selected distances. As shown in Figure 11, the ADuM2250/
ADuM2251 are 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
must be placed 5 mm away from the ADuM2250/ADuM2251
to affect the operation of the component.
Note that at combinations of strong magnetic fields and high
frequencies, any loops formed by printed circuit board 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.
1000
100
10
DISTANCE = 100mm
1
DISTANCE = 5mm
0.1
0.01
0.01
1k
10k
100k
1M
10M
MAGNETIC FIELD FREQUENCY (Hz)
10k
1M
10M
100k
MAGNETIC FIELD FREQUENCY (Hz)
100M
06670-010
0.001
1k
DISTANCE = 1m
Figure 10. Maximum Allowable External Magnetic Flux Density
Rev. D | Page 12 of 16
Figure 11. Maximum Allowable Current for Various
Current-to-ADuM2250/ADuM2251 Spacings
100M
06670-011
The ADuM2250/ADuM2251 are extremely immune to external
magnetic fields. The limitation on the magnetic field immunity
of the ADuM2250/ADuM2251 is set by the condition in which
induced voltage in the receiving coil of the transformer is sufficiently large to either falsely set or reset the decoder. The following
analysis defines the conditions under which this may occur. The
3 V operating condition of the ADuM2250/ADuM2251 is
examined because it represents the most susceptible mode of
operation.
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.
MAXIMUM ALLOWABLE CURRENT (kA)
MAGNETIC FIELD IMMUNITY
Data Sheet
ADuM2250/ADuM2251
OUTLINE DIMENSIONS
10.50 (0.4134)
10.10 (0.3976)
9
16
7.60 (0.2992)
7.40 (0.2913)
1
8
1.27 (0.0500)
BSC
0.75 (0.0295)
45°
0.25 (0.0098)
2.65 (0.1043)
2.35 (0.0925)
0.30 (0.0118)
0.10 (0.0039)
COPLANARITY
0.10
10.65 (0.4193)
10.00 (0.3937)
SEATING
PLANE
0.51 (0.0201)
0.31 (0.0122)
8°
0°
1.27 (0.0500)
0.40 (0.0157)
0.33 (0.0130)
0.20 (0.0079)
03-27-2007-B
COMPLIANT TO JEDEC STANDARDS MS-013-AA
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.
Figure 12. 16-Lead Standard Small Outline Package [SOIC_W]
Wide Body
(RW-16)
Dimensions shown in millimeters (inches)
12.85
12.75
12.65
1.93 REF
16
9
PIN 1
MARK
1
8
10.51
10.31
10.11
2.64
2.54
2.44
2.44
2.24
0.30
0.20
0.10
COPLANARITY
0.1
1.27 BSC
0.46
0.36
0.71
0.50
0.31
0.25 BSC
GAGE
PLANE
SEATING
PLANE
45°
1.01
0.76
0.51
COMPLIANT TO JEDEC STANDARDS MS-013-AC
Figure 13. 16-Lead Standard Small Outline Package, with Increased Creepage [SOIC_IC]
Wide Body
(RI-16-2)
Dimensions shown in millimeters
Rev. D | Page 13 of 16
0.32
0.23
8°
0°
11-15-2011-A
7.60
7.50
7.40
ADuM2250/ADuM2251
Data Sheet
ORDERING GUIDE
Model 1, 2
ADuM2250ARWZ
ADuM2250ARWZ-RL
ADuM2250WARWZ
ADuM2250WARWZ-RL
ADuM2250ARIZ
ADuM2250ARIZ-RL
ADuM2251ARWZ
ADuM2251ARWZ-RL
ADuM2251WARWZ
ADuM2251WARWZ-RL
ADuM2251ARIZ
ADuM2251ARIZ-RL
1
2
Number of
Inputs,
VDD1 Side
2
2
2
2
2
2
2
2
2
2
2
2
Number
of Inputs,
VDD2 Side
2
2
2
2
2
2
1
1
1
1
1
1
Maximum
Data Rate
(Mbps)
1
1
1
1
1
1
1
1
1
1
1
1
Temperature
Range
−40°C to +105°C
−40°C to +105°C
−40°C to +125°C
−40°C to +125°C
−40°C to +105°C
−40°C to +105°C
−40°C to +105°C
−40°C to +105°C
−40°C to +125°C
−40°C to +125°C
−40°C to +105°C
−40°C to +105°C
Package Description
16-Lead SOIC_W
16-Lead SOIC_W, 13” Tape and Reel
16-Lead SOIC_W
16-Lead SOIC_W, 13” Tape and Reel
16-Lead SOIC_IC
16-Lead SOIC_IC, 13” Tape and Reel
16-Lead SOIC_W
16-Lead SOIC_W, 13” Tape and Reel
16-Lead SOIC_W
16-Lead SOIC_W, 13” Tape and Reel
16-Lead SOIC_IC
16-Lead SOIC_IC, 13” Tape and Reel
Package
Option
RW-16
RW-16
RW-16
RW-16
RI-16-2
RI-16-2
RW-16
RW-16
RW-16
RW-16
RI-16-2
RI-16-2
Z = RoHS Compliant Part.
W = Qualified for Automotive Applications.
AUTOMOTIVE PRODUCTS
The ADuM2250W and ADuM2251W models are available with controlled manufacturing to support the quality and reliability
requirements of automotive applications. Note that these automotive model may have specifications that differ from the commercial
model; therefore, designers should review the Specifications section of this data sheet carefully. Only the automotive grade products
shown are available for use in automotive applications. Contact your local Analog Devices account representative for specific product
ordering information and to obtain the specific Automotive Reliability reports for these models.
Rev. D | Page 14 of 16
Data Sheet
ADuM2250/ADuM2251
NOTES
Rev. D | Page 15 of 16
ADuM2250/ADuM2251
Data Sheet
NOTES
I2C refers to a communications protocol originally developed by Philips Semiconductors (now NXP Semiconductors).
©2007–2015 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D06670-0-7/15(D)
Rev. D | Page 16 of 16
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