Date: 25/08/2010

Hot swappable, dual I2C digital isolator from Analog Devices

Analog Devices is sampling theADuM1250W iCoupler Digital Isolator, which ADI claims is the industry’s first automotive grade products to provide true bidirectional isolation for the lower cost I2C serial bus. This device is based on ADI’s iCoupler digital isolation technology.

The ADuM1250W iCoupler Digital Isolator is hot swappable, dual I2C digital isolator. ADI says that the device reduces board space by as much as 80 percent and reduces the system cost associated with isolating I2C buses. This devices eliminates optocouplers and support circuitry previously required in isolated I2C interfaces. The ADuM1250W is AEC-Q100 qualified and is based on ADuM125x family of I2C isolators. This digital isolator is used in a wide range of industrial, instrumentation, networking and other applications.

I2C bus advantages and the need for isolation as said by ADI:
The I2C bus is a cost-effective, two wire interface between controllers and peripheral devices such as data converters, memory products, switches, sensors and power supply ICs. The bus uses bidirectional lines to transmit and receive signals over the same wire, allowing two-wire signaling of clock and data. This reduces complexity and cost by eliminating extra wiring and components. In a variety of HEV and automotive applications, controllers or peripherals are isolated from the bus to avoid interference or harmful voltage levels. Typically, isolation has been achieved with optocouplers, but doing so increases the cost and complexity of the I2C interface because unidirectional optocouplers must be accommodated by separating each of the two bidirectional I2C channels into two unidirectional channels. The resultant four unidirectional channels are then each isolated with an optocoupler and recombined into two bidirectional channels. The additional circuitry associated with the bidirectional/unidirectional conversions and the isolation of the four unidirectional channels adds complexity and cost that offset the intended benefits of the I2C bus. With the ADuM1250W isolator, this complexity and cost is avoided as a single component directly provides bidirectional isolation to both of the I2C lines. This small, complete isolation device ensures the signal integrity of the bidirectional I2C bus while reducing component count, cost, board space, and complexity.

The key features of ADuM1250W iCoupler Digital Isolator include:

AEC-Q100 qualified, 125?C operation, supports the quality and reliability requirements of automotive applications
True bi-directional isolated data paths eliminate the need for buffers and other external components
Industry standard I2C interface ensures reliable operation with I2C compliant peripherals
1MHz operation provides ample bandwidth to operate with high performance peripherals and devices
3.0- to 5.5-V supply/logic levels enables flexible operation and level shifting

Package: Small surface mount 8-lead SOIC

Operating temperature range: –40°C to +125°C

Pricing and Availability
Product Sample Availability Price in 10,000s Packaging
ADuM1250W NOW $2.21 8-lead SOIC_narrow