• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 32 subscribers
  • Views 161 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TCAN1043-Q1: VSUP Connection Inquiry

Evan Wang
Expert 7130 points
Part Number: TCAN1043-Q1

Hi team,

For TCAN1043-Q1, if we do not need external wake up(LWU) mechanism, could we connect the VSUP pin to VCC pin directly?

As long as the VSUP is above UVVSUP, it should be fine right? 

Since the IC has UVVSUP protection so we can't leave it as floating, am I right?

Customer think if they connect the VBAT to the VSUP then it will increase the potential failure rate so they prefer to connect VSUP to VCC.

Kindly let us know if you have any concerns,

Thank you.

  • 0
    TI__Mastermind 19930 points

    Hi Evan.

    What is their VBAT voltage? Connecting VSUP to VCC has the risk of violating the VCC abs max rating so I won't recommend to do that.

    In addition, UVVCC has a 3.5V min falling under voltage detection which is higher then the 3.0 min on UVSUP. When VCC becomes unavailable due to this undervoltage condition, reliable CAN communication will not be possible as the 5V supply is needed by the CAN driver. If the UVVCC condition remains for tUV the device will assume there has been some issue with the local supply and move to the lowest power state (sleep mode) in order to have minimal impact on the system. It simply means if their VBAT drop under 3.5V the device cannot communicate.

    Regards,

    Sean

  • 0 in reply to Sean Guo
    TI__Expert 7130 points

    Hi Sean,

    I mean since we do not need the INH and LWU, so we just simply connect the VSUP to VCC pin directly.

    From below figure, could we left INH floating in this case?

    You can see we didn't connect VSUP to VBAT.

    The demo in the datasheet shows using INH pin to power 3.3V and 5V Vreg for VIO and VCC source but we have other MCU to control it so no need for VSUP/INH.

  • 0 in reply to Evan Wang
    TI__Mastermind 19930 points

    Hi Evan,

    Evan Wang said:
    From below figure, could we left INH floating in this case?

    Yes INH can be left floating.

    You can supply both VSUP and VCC with 5V. If VSUP is below UVSUP threshold the device will enter protected mode and it will not transmit or receive data.

    Regards,

    Sean