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TCAN1043-Q1: Does it work well to set EN=NSTB=H before VCC=5V?

Yoshikazu Kawasaki
Expert 3510 points
Part Number: TCAN1043-Q1

Hello,

My customer understands TCAN1043-Q1 will be in normal operation when NSTB=EN=H from the datasheet, but will it have to be set after VCC=5V?  Or can it be before VCC=5V?  They'd like to confirm the order of NSTB=EN=H for VCC=5V.  Would you please tell me that?  It's not described exactly in the datasheet.

Best Regards,

Yoshikazu Kawasaki

  • 0
    TI__Guru 53515 points

    Hi Yoshikazu-san,

    There is no specific power-up sequence required by TCAN1043-Q1. While Vcc and/or Vio are below their undervoltage thresholds, the device will be in Sleep Mode and the CAN driver will remain inactive as to not disturb the bus - regardless of the state of EN or nSTB. Once these pins are supplied, the device can transition to Normal Mode (with nSTB and EN high). As long as all logic pins are stable once power is properly supplied (TXD pin should be stable high as to not inadvertently drive a dominant to the bus), TCAN1043-Q1 will startup with no glitches or bus disturbance. 

    For a more complete description of device states when various supply pins are active/inactive, see Table 3 on the datasheet. 

    Let me know if you have any more questions.

    Regards,
    Eric Schott

  • 0 in reply to Eric Schott1
    TI__Expert 3510 points

    Hello Eric,

    Thank you for your quick reply.  The table 3 in the datasheet doesn't show the sequence of power/signal pins, so I understand there is no specific sequence for those pins.  I also understand there is no specific sequence for power-down like normal mode to standby mode.  Operating modes will be determined by the state of power/signal pins regardless of the sequence how those pins move.

    Best Regards,

    Yoshikazu Kawasaki

  • 0 in reply to Yoshikazu Kawasaki
    TI__Guru 53515 points

    Hi Yoshikazu-san,

    Your understanding on these is correct. No power-on or power-off sequence is required. The only modes the device will switch between without controller input are GotoSleep, Sleep, and Standby Modes depending on timing and wake conditions. All other mode changes will be in response to power/signal inputs. 

    Regards,
    Eric Schott