SLLSFM2A November 2024 – October 2025 TCAN2855-Q1 , TCAN2857-Q1
PRODUCTION DATA
VSUP is the primary input supply rail required for the device to function properly. There are three voltage levels monitored by the device, power on reset and two under-voltage level. For all functions and output voltage rails to be in regulation the device must exceed UVSUP5R. If VSUP is in under-voltage, the device loses the supply source needed to keep the internal regulators in regulation. This causes the device to go into a state where communication between the microprocessor and the TCAN285x-Q1 is disabled. In this mode, the device is still active but VCC1, VCC2 and VEXCC can be experiencing under voltage events and other functions is not active, like watchdog. No mode change can take place. The device is not able to receive information from the bus; thus, does not pass any signals from the bus, including any Bus Wake using BWRR signals to the microprocessor. VCC1 determines which UVSUP level, UVSUP33R/F or UVSUP5R/F. If VSUP keeps ramping down and drops below VSUP(PU)F, the device enters powered off state. When VSUP returns, the device comes up as if there is an initial power on. All registers are cleared and the device has to be reconfigured from the stored EEPROM values that are retained. During an UVSUP event, the device has some functionality. The LDOs are in pass through mode until VSUP ≥ UVSUPxxR and VCC1 exceeds the UVCC1xxR level. The device transitions to restart mode if VCC1 < UVCC1xxF and stays in restart mode until UVCC1xxR is cleared (the restart timer, tRSTTO, is ignored).
For devices where VCC1 is 5V, UVSUP5R/F is the only VSUP under-voltage rail monitored. When VSUP drops below UVSUP5F, The CAN and LIN transceivers are turned off and LDOs are in pass thru mode. See Table 8-13 for relationship between VSUP, VCC15, VCAN, device mode and transceivers.
When VCC1 is 3.3V, both UVSUP33R/F and UVSUP5R/F are monitored. When powering up, VSUP has to exceed UVSUP33R for VCC1 to be in regulation and above UVSUP5R for VCC2 and other functions of the device to work properly. When VSUP is ramping down, UVSUP5F is the first UVSUP level that sets an UVSUP5 interrupt flag, register 8’h52[4], and turns off the CAN transceiver. The LIN transceiver is still functioning, but does not always meet the data sheet electrical and timing specifications. If VSUP keeps dropping, the next level is UVSUP33F. When this is reached, the UVSUP33 interrupt flag is set, register 8’h52[3]. When this level is reached, the LIN transceiver is turned off. See Table 8-14 for relationship between VSUP, VCC133, VCAN, device mode and transceivers.
Under-voltage on the high-side switches power, VHSS, is indicated by interrupt INT_4 register 8'5A[0] UVHSS. How the high-side switches behave due to an UVHSS event is determined by HSS_CNTL3 register 8'h4F[6:5].
| VSUP | VCC1 | VCAN | DEVICE STATE | CAN TRANSCEIVER | LIN TRANSCEIVER |
|---|---|---|---|---|---|
| > UVSUP5 | > UVCC15 | > UVCAN | Normal or Standby | As Programmed | As Programmed |
| > UVSUP5 | < UVCC15 | NA | Restart | Wake capable or off | Wake capable or off |
| > UVSUP5 | > UVCC15 | > UVCAN | Previous State | As Programmed | As Programmed |
| > UVSUP5 | > UVCC15 | > UVCAN | Previous State | As Programmed | As Programmed |
| > UVSUP5 | > UVCC15 | < UVCAN | Previous State | Listen, Wake capable or off | As Programmed |
| VSUP | VCC1 | VCAN | DEVICE STATE | CAN TRANSCEIVER | LIN TRANSCEIVER |
|---|---|---|---|---|---|
| > UVSUP5 | > UVCC133 | > UVCAN | Normal or Standby | As Programmed | As Programmed |
| > UVSUP5 | < UVCC133 | NA | Restart | Wake capable or off | Wake capable or off |
| > UVSUP5 | > UVCC133 | > UVCAN | Previous State | As Programmed | As Programmed |
< UVSUP5 > UVSUP33 | > UVCC133 | NA | Normal or Standby | Off | As Programmed |
< UVSUP5 > UVSUP33 | < UVCC133 | NA | Restart | Off | Off |
| > UVSUP5 | > UVCC133 | < UVCAN | Normal or Standby | Listen, Wake capable or off | As Programmed |