
Hot Swappable Dual I
2
C Isolators
ADuM1250/ADuM1251
FEATURES
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2006 Analog Devices, Inc. All rights reserved.
Fax: 781.461.3113
www.analog.com
Bidirectional I
2
C 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
8-lead SOIC lead-free package
High temperature operation: 105°C
Safety and regulatory approvals
UL recognition
2500 V rms for 1 minute per UL 1577
CSA Component Acceptance Notice #5A (pending)
VDE Certificate of Conformity (pending)
DIN EN 60747-5-2 (VDE 0884 Part 2): 2003-01
DIN EN 60950 (VDE 0805): 2001-12; DIN EN 60950: 2000
V
IORM
= 560 V peak
APPLICATIONS
Isolated I
2
C, SMBus, or PMBus interfaces
Multilevel I
2
C interfaces
Power supplies
Networking
Power-over-Ethernet
FUNCTIONAL BLOCK DIAGRAMS
ENCODE
DECODE
DECODE
ENCODE
ENCODE
DECODE
DECODE
ENCODE
V
DD1
SDA
1
SCL
1
GND
1
V
DD2
SDA
2
SCL
2
GND
2
1
2
3
4
8
7
6
5
0
Figure 1. ADuM1250 Functional Block Diagram
ENCODE
DECODE
ENCODE
DECODE
DECODE
ENCODE
V
DD1
SDA
1
SCL
1
GND
1
V
DD2
SDA
2
SCL
2
GND
2
1
2
3
4
8
7
6
5
0
Figure 2. ADuM1251 Functional Block Diagram
GENERAL DESCRIPTION
The ADuM1250/ADuM1251
1
are hot swappable digital
isolators with non latching bidirectional communication
channels compatible with I
2
C interfaces. This eliminates the
need for splitting I
2
C signals into separate transmit and receive
signals for use with standalone optocouplers.
The ADuM1250 provides two bidirectional channels
supporting a complete isolated I
2
C interface. The ADuM1251
provides one bidirectional channel and one unidirectional
channel for those applications where a bidirectional clock is not
required.
Both the ADuM1250 and ADuM1251 contain hot swap
circuitry to prevent glitching data when an unpowered card is
inserted onto an active bus.
These isolators are based on
i
Coupler chip scale transformer
technology from Analog Devices, Inc.
i
Coupler is a magnetic
isolation technology with functional, performance, size, and
power consumption advantages as compared to optocouplers.
With the ADuM1250/ADuM1251,
i
Coupler channels can be
integrated with semiconductor circuitry, which enables a
complete isolated I
2
C interface to be provided in a small
form factor.
1
Protected by U.S. Patents 5,952,849 and 6,873,065. Other patents pending.
Rev. 0
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
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