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TCAN1043H-Q1: TCAN1043H-Q1

Tsutomu Hibi
Prodigy 50 points
Part Number: TCAN1043H-Q1
Other Parts Discussed in Thread: TCAN1043

Tool/software:

Dear TI team, 

I am trying to confirm the operation of the wake up function of the TCAN1043 and now I am having problems.
Could you please advise?

When I turn on the first external power supply, INH is output Hi during the voltage rise of VSUP.

However, we would like INH to be output after external CAN singal pattern is input.

- Vext = 48V, input to VSUP

- RBIAS =80.6kohm

- RSERIES=80.6kohm

IHN is output under the condition that VSUP=WAKE and VCC=VIO=Lo.

Please let me know the cause.

Best regards,

T. Hibi.

  • 0
    TI__Guru 50795 points

    Hi Hibi,

    The INH signal for this device is only off when the device is in sleep mode or unpowered on Vsup. When Vsup is first applied, the transceiver moves into standby mode (INH = high) so that the local node can initialize itself for a POR condition. If the system would like the node to go into a low power mode after this, the nSTB should be driven low while EN is high to enter go-to-sleep mode followed by sleep mode. This will set INH into a high impedance state (off). Once in sleep mode, the device will respond to CAN activity on the CAN bus (wake up pattern or WUP) by waking into standby mode and driving INH high. 

    Does this sequence work for your desired application or is there something else in your system that needs to happen during initial application of the Vsup supply? 

    Regards, 
    Eric Schott

  • 0 in reply to Eric Schott1
    Prodigy 50 points

    Thank you so much for your reply.

    I will study the startup sequence including this operation.

    Best regards,

    Tsutomu Hibi.

  • 0 in reply to Tsutomu Hibi
    Prodigy 50 points

    Dear Eric-san, 

    I have one additional question.

    I nderstand the INH operation, but I would like to know the nFault operation.

    What is the state when nFault goes Hi?

    Basically, I am understanding that it goes Hi when the it is ativated by WUP upon entering normal mode.

    However, after power-up, VCC is input Hi and EN and nSTB are set to Hi, they are set to Lo again, then, nFault goes to Hi. WUP pattern is not input.

    Is this behavior correct?

    Best regards,

    Tsutomu Hibi.

  • 0 in reply to Tsutomu Hibi
    TI__Guru 50795 points

    Hi Tsutomu-san,

    The nFAULT pin relays information about the device state based on the device mode. Table 8-1 in the datasheet describes all of the causes this pin will indicate a flag is set (nFAULT is low). 

    Also note that the nFAULT pin is a push-pull output that is supplied by the Vio supply. If Vio is not available, the nFAULT pin will be high impedance and will likely fall to ground. In the scope shots you show here, nFAULT is going low when Vcc (assumed to be shared with Vio) is low. This would be expected as the power source for this pin is needed in order for the pin to remain high. 

    Regards, 
    Eric Schott