Analog Devices Automotive Grade I2C Isolators Simplify Hybrid-Electric Automotive Designs
Analog Devices, Inc. (ADI) is introducing what it says is the industry’s first automotive grade products to provide true bidirectional isolation for the lower cost I²C serial bus. Based on ADI’s proprietary iCoupler® digital isolation technology, the ADuM1250W hot swappable, dual I²C digital isolator reduces board space by as much as 80% and greatly reduces the system cost associated with isolating I²C buses. This is accomplished by eliminating optocouplers and support circuitry previously required in isolated I²C interfaces.
ADI says the ADuM1250W is the industry’s first I²C digital isolator to carry an AEC-Q100 qualified -40 to +125°C automotive temperature rating and is based on the ADuM125x family of I²C isolators that have been in volume production for over three years in a wide range of industrial, instrumentation, networking and other applications.
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.
ADuM1250W ICoupler® Digital Isolator features and benefits include: AEC-Q100 qualified, 125°C operation, supports the quality and reliability requirements of automotive applications; small surface mount 8-lead SOIC package saves up to 80% board space; 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; and 3.0- to 5.5V supply/logic levels enables flexible operation and level shifting.
The AduM1250W is priced (in 10,000 pieces) at $2.21.
