Hi,
1. VCC powers the CAN driver circuitry, particularly the CAN_H and CAN_L lines, so it is necessary when the transceiver is actively transmitting and receiving CAN signals.
VIO powers the logic-level interface for the microcontroller, handling digital signals on the TXD, RXD, STB_N, EN and ERR_N.
VBAT is the primary battery power supply. The low power receiver with bus monitor, WAKE circuits and INH are supplied via VBAT.
You can find additional information in the AH1014 , chapters 7.1 and 6.1.
2. When VCC and VIO are turned off (often achieved by disabling them via the INH pin to reduce power consumption), the transceiver enters Sleep mode, where only VBAT is supplying power.
In this configuration, the TJA1043 retains wake-up functionality, including the ability to monitor for a dedicated wake-up pattern or a digital wake-up signal on the WAKE pin. This allows the transceiver to transition to Normal mode when a wake-up event is detected, even if VCC and VIO are off.
Other functionality, such as CAN communication or full interfacing with the MCU, will be unavailable until VCC and VIO are re-enabled.
3. As I mentioned before, there is available the AH1014 with necessary information for HW and SW engineers to succesfully implement our 3rd generation HS-CAN transceivers including the TJA1043.
https://www.nxp.com/docs/en/supporting-information/AH1014.pdf
BRs, Tomas
