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TCAN1043G-Q1: EN pin state during Standby

Akihiro Hirata
Expert 6200 points
Part Number: TCAN1043G-Q1
Other Parts Discussed in Thread: TCAN1043A-Q1,

Hello team,

Regarding TCAN1043G-Q1 and TCAN1043A-Q1, we would like to know EN pin state on the state diagram.
In the below attached state diagram, it describes EN: L in the Standby Mode.
However is this always true?
For example, if the TCAN1043G/A-Q1 with EN=H wakes up from the Sleep Mode, EN = H even in the Standby Mode.

Regards,

Hirata

  • +1
    TI__Genius 15345 points

    Hi Hirata,

    I would like to make a quick correction. The EN pin going high does not wake your device out of sleep mode. You also have to bring the nSTBY pin high as well to exit sleep mode. However, if you do this you do not go into standby mode. First let's keep in mind that in order to enter sleep mode EN is high and nSTBY is low. Now in order to exit sleep mode:

    • If EN is low and nSTBY goes from low to high -> You enter silent mode
    • If EN is high and nSTBY goes from low to high -> You enter normal mode.

    In both of these cases there is no way to enter standby mode by toggling a pin. The only way to enter standby from sleep is to use a Wake Event, LWU or a WUP on the bus. If you toggle your pins you will either enter silent mode or normal mode.

    To take this further, the main purpose behind sleep mode is your INH pin would turn off which turns off your voltage regulator for the board. So your MCU is off and it can no longer control the EN and STBY pins. Standby mode is used to turn on your INH pin after a Wake Event. It gives your board time to turn on the regulator and wait for your MCU to power up. So when your voltage regulator turns on and your MCU has control over the EN and STBY pins, it can choose which state it goes to.

    If you have control over your EN and STBY pins in sleep mode then that means that you never turned off your regulator. Which means that you don't need standby mode which is why the state machine doesn't have a way to go from sleep to standby using the EN and nSTBY pins.

    I hope this makes sense.

    Best,

    Chris