General Description
The ADuM1253 offers two open-drain channels, one
unidirectional and one bidirectional for applications,
such as I2C, that require data to be transmitted in both
directions on the same line but have a unidirectional
clock. To prevent latch-up action, side 1 outputs
comprise special buffers that regulate the logic-low
voltage at 0.64V, and the input logic-low threshold is at
least 50mV lower than the output logic-low voltage. Side
2 features conventional buffers that do not regulate
logic-low output voltage.
The ADuM1253 features independent 1.71V to 5.5V
supplies on both side 1 and side 2 of the isolator. The
device operates up to 2MHz. The ultra-low standby
current of 21μA per side is ideal for battery-operated
systems.
The ADuM1253 provides a disturbance-free bus
connection for hot-plug connections on side 2 by first
precharging the bus pins and then monitoring the bus
state for either an idle bus or detection of a I2C stop
condition before connecting side 1 and side 2.
The ADuM1253 is available in an 8-pin narrow SOIC
package. The device is rated for operation at ambient
temperatures of -40°C to +125°C.

Benefits and Features
• Low VOL(MAX) for Greater I2C Device Compatibility
• Side 1: 0.69V
• Side 2: 0.4V
• Ultra-Low-Power Consumption for Longer Battery
Life
• 142μA (typ) per Channel at 400kHz
• Wide Independent VDD1/VDD2 Supply Range
Supports More Logic Voltage Levels and Allows
Level Shifting
• 1.71V to 5.5V for Both Sides
• Hot-Swappable Side 2 I/O Prevents Data Corruption
• Initial Side 2 Connection Occurs at Bus Idle or
Stop States
• Bidirectional I2C Transfer up to 2MHz SCL
• Strong Current Sinking Enables Lower RPULL-UP
Values for Faster Bus Speeds
• Side 1: 5mA
• Side 2: 50mA
• Robust Galvanic Isolation of Digital Signals
• Continuously Withstands (VIOWM)
- 8-Narrow SOIC: 445VRMS
• Withstands ±10kV Surge per IEC 61000-4-5
• Package with Creepage and Clearance
- 8-Narrow SOIC: 4mm
• Safety and Regulatory Approvals (Pending)
• IEC 60747-17 (Pending)
- Reinforced VIORM Narrow SOIC: 630VPEAK
• UL 1577 (Pending)
- 8-Narrow SOIC: 3000 VRMS for 1min
• IEC/EN/CSA 62368-1 (Pending)
• IEC/EN/CSA 61010-1 (Pending)
• CAN/CSA-C22.2 No. 14–18 (Pending)

Key Applications
• Isolated I2C/SMBus Interface
• Battery Management Systems
• Power Over Ethernet (PoE)
• Motor Control Systems