SLLA475 December 2020 TCAN1144-Q1 , TCAN1146-Q1
The TCAN1144-Q1 and TCAN1146-Q1 provides advanced bus fault detection. TCAN1146-Q1 is used for illustration purposes. The device can determine certain fault conditions and set a status/interrupt flag so that the MCU can understand what the fault is. Detection takes place and is recorded if the fault is present during four dominant to recessive transitions with each dominant bit being > 1.5 μs. As with any bus architecture where termination resistors are at each end not every fault can be specified to the lowest level, meaning exact location. The fault detection circuitry is monitoring the CANH and CANL pins (currents) to determine if there is a short to battery, short to ground, short to each other or opens. From a system perspective, the location of the device also determine what can be detected. See device data sheet for detailed desciption of the CAN bus fault diagnostic.