SLLA475 December 2020 TCAN1144-Q1 , TCAN1146-Q1
There are three under voltage events monitored in the TCAN1144-Q1 and TCAN1146-Q1, VSUP, VIO and VCC. The three supply terminals are input sources for the TCAN114x-Q1 and have under voltage detection circuitry which places the device in a protected state if an under voltage fault occurs, UVSUP, UVCC and UVIO. This protects the bus during an under voltage event on these terminals. If VSUP is under voltage the device loses the source needed to keep the internal regulators active. This causes the device to go into a state where communication between the microprocessor and the TCAN114x-Q1 is disabled. The TCAN114x-Q1 is not able to receive information from the bus; and thus, does not pass any signals from the bus, including any Bus Wake via BWRR signals to the microprocessor.
Safety mechanisms SM-5, SM-6 and SM-7 cover this.| VSUP | VCC | DEVICE STATE | BUS | RXD |
|---|---|---|---|---|
| > UVSUP | > UVCC | Normal | Per TXD | Mirrors Bus |
| > UVSUP | < UVCC | Fail-safe or Sleep | High Impedance | High (Recessive) |
| < UVSUP | NA | Power off | High Impedance | High Impedance |
| VSUP | VIO | VCC | DEVICE STATE | BUS | RXD |
|---|---|---|---|---|---|
| > UVSUP | > UVIO | > UVCC | Normal | Per TXD | Mirrors Bus |
| > UVSUP | > UVIO | < UVCC | Fail-safe or Sleep | High Impedance | High (Recessive) |
| < UVSUP | > UVIO | NA | Power Off | High Impedance | High (Recessive) |
| > UVSUP | < UVIO | > UVCC | Fail-safe or UVIO Protected —> Sleep | High Impedance | High Impedance |
| > UVSUP | < UVIO | < UVCC | Fail-safe or Sleep | High Impedance | High Impedance |
| < UVSUP | < UVIO | NA | Power Off | High Impedance | High Impedance |