Automotive ISO26262 safety requirements met by LIN transceiver chip

August 13, 2013 // By Paul Buckley
ams has  introduced the AS8530 which claims to be the world’s first miniature power/transceiver IC to support LIN slave applications, and which also complies with the ISO26262 functional safety standard.

The AS8530 is a power management and communication device that includes a LIN 2.1 transceiver, a 50-mA LDO to supply a local MCU and a reset generator, in an 8-pin SOIC 8 package. As a differentiator, the AS8530 offers a series of system management functions through a shared pin serial interface, all within an 8-pin SOIC8 package.
The addition of enhanced diagnosis functions provides built-in support for the requirements of ISO26262. A two-wire serial port routed through shared Enable and TX pins allows the device to read out status registers and provide diagnosis information to the system’s microcontroller. It also supports additional features such as a window watchdog function and access to back-up registers to store data when the microcontroller shuts down.
These features are crucial in the design of ISO26262-compliant systems, which must be able to cease operation safely when in a fault condition, before the vehicle is at risk of endangering passengers or other road users.
The AS8530 is suitable for any LIN-networked sensor and actuator slaves including those found in door modules, sunroofs and headlight positioning units. It is suited for safety-critical systems that require an ASIL grading under the provisions of the ISO26262 standard.
The on-chip LDO provides a factory-selectable 3.3V or 5V output. The chip also offers a reset generator and an output voltage monitor and has a unique chip ID to support traceability requirements. Power-saving stand-by and sleep modes, as well as the normal operating mode, can be triggered via the Enable pin. The  AS8530 LIN IC costs $2.21 (1,000). An evaluation kit for the interface IC AS8530, the AS8530 adapter board, is available online, priced at $70.
ams; www.ams.com/Interface/LIN-Bus-System/AS8530