Local Interconnect Network. Today, we'll discuss the coexistence of CAN and LIN in automotive networks. We'll do a brief LIN overview, discuss the physical layer, and then follow on with the LIN frame structure, and discuss the key LIN features to consider when choosing a transceiver. We'll also discuss the conformance and EMC test reports that are available for Texas Instruments LIN transceivers, and discuss the different package options available.

In today's automobiles, CAN is the main bus that connects multiple nodes throughout the vehicle. It's a differential two-wire interface. Classic CAN operate up to 1 megabit per second, and CAN FD operates up to 5 megabits per second. LIN is a sub-bus. It's a single-ended, one-wire interface that communicates at 20 kilobits per second.

So what is LIN? LIN stands for Local Interconnect Network. The core of LIN is a serial network protocol controller and a physical layer transceiver. The transceiver transmitter converts the logic level LIN protocol data stream on the TXD input into a VBAT level LIN bus signal using a current-limited, wave-shaping driver, which reduces electromagnetic emissions.

The transceiver receiver converts the high-voltage data stream from the LIN bus to logic level signals that are sent to the microprocessor through the RXD pin. The network protocol controller provides the synchronization, logic, error detection, and other features that are usually associated with LIN. The network relies on a single master communicating with up to 16 slave devices.

LIN is a broadcast, serial, one-wire interface, which is typically implemented as a sub-bus of a CAN network. It allows automotive manufacturers to reduce cost by offloading low-speed, non-safety critical functions from a two-wire CAN bus to a one-wire bus. One master coordinates communication between up to 16 slave devices on the network.

The LIN physical layer signals either recessive or dominant. To indicate dominant, the LIN pin voltage must be less than or equal to 0.4 of the system's supply voltage. It is recessive when the LIN pin voltage is greater than or equal to 0.6 of the system's supply voltage.

The LIN protocol specification defines all types of frames that may be sent on the LIN bus, the fields that make up each type of frame, and the order of the bits in each field. The physical layer is unchanged for LIN specification versions 1.3 through 2.2A.

Texas Instruments LIN devices feature many benefits for customers. They operate off 12 and 24 volt battery systems, providing 45 and 58 volt bus fault protection; transceiver transmitter, supporting up to 20 kilobits per second; transceiver receiver, supporting 100 kilobit per second data rates to support inline programming of LIN nodes; multiple node wake up methodologies; small package options; 8 kV HBM and IEC 6100-4-2 ESD; dominant estate time-out support; undervoltage and thermal shut down; integrated LDOs; as well as watchdogs.

Texas Instruments LIN devices also have conformance and EMC reports for OEM certification. For conformance, LIN OSI Layer 1 Physical Layer reports are available, as well as SAE J2602-2. For EMC, the G5 EMC report, commonly referred to as the IBEE Zwickau report, is available as well. The SAE J2962-1 report is also available.

Texas Instruments provides a full-featured, 8-pin LIN transceiver, using industry-standard pinout in both SOIC and QFN packages. The full-featured transceiver, in addition to the LIN transceiver, has the inhibit and wake pin for system power control and high-voltage input wake. There is also a reduced feature 8-pin LIN transceiver in both the SOIC and QFN package as well. These transceivers do not have the inhibit and wake pins.