Star coupler links two FlexRay systems

October 08, 2012 // By Christoph Hammerschmidt
Chipmaker Elmos AG introduces the world's first FlexRay dual star coupler. The E981.57 is certified according to the FlexRay Electrical Physical Layer (EPL) specification V3.0 and meets carmakers requirements with regard to electromagnetic interference (EMI) and electrostatic discharge (ESD).

The star coupler connects two branches of a FlexRay network. Towards this end, the chip contains two independent physical bus drivers for transmission and reception of FlexRay messages. An integrated SPI-compatible interface enables configuration and mode control as well as diagnosis data exchange through a microcontroller. In addition, a communication interface is integrated which enables designers to use the device as standard transceiver. In autonomous mode the star coupler exerts the function of a repeater; in this case no microcontroller is required.

The entry level model E981.57 features two channels. In addition, Elmos also offers a quadruple star coupler in the same package, the model E981.56. Thus, customers have the option to implement systems with two, four, six or eight channels on a single PCB layout and configure them according to their respective needs. For cases where just one channel is required, Elmos offers the E981.55 FlexRay transceiver. All devices are equipped with wake-up functionality.

The E981.56 /57 comes in a 44-pin QFN package with 9mm edge length. The chips are designed for an operating temperature range from -40°C to +125°C. Qualification according to AEC-Q100 has been concluded successfully.

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