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TLIN1021A-Q1: Sleep Mode Behaviour

Josef Warta
Expert 4060 points
Part Number: TLIN1021A-Q1

Hello Team, my customer needs an explanation regarding sleep-mode due to different behaviour what he found/measured.

INH signal is de-activated (Pull-Down, LOW) after under-voltage event on VSUP-pin (VSUP<4.5V)
After asserting VSUP-pin to normal supply INH stays at de-activated. It is not come back to HIGH (activated).

By connecting LIN to GND a WAKE-UP procedure starts. (to emulate a wake-up)
This means TLIN was in SLEEP state during undervoltage on VSUP.

With STAND-BY mode INH should stay on. But measurements show LOW/de-activated.

Also Normal Mode is not possible because this needs EN=HIGH and this is due customer application fixed.

According state diagram this behaviour cannot be explained or is there something missing?

According datasheet the only way to transfer to SLEEP mode is from NORMAL mode.

Is there any special condition during 'under-voltage' event which could explain this?

Many Thanks

Josef

  • 0
    TI__Genius 15345 points

    Hi Josef,

    Can you provide a schematic of your device? After an under voltage event the device will always enter the unpowered system state.

    Josef Warta said:
    By connecting LIN to GND a WAKE-UP procedure starts. (to emulate a wake-up)
    This means TLIN was in SLEEP state during undervoltage on VSUP.

    After the device receives the WAKE signal do you see the INH pin go from High to low.

    Josef Warta said:
    Also Normal Mode is not possible because this needs EN=HIGH and this is due customer application fixed.

    I'm unsure what you mean by this. Are you saying the customer cannot use the normal mode of this device? What mode is this device expected to be in and communicate in?

    Can you attach some scope shots of these tests including the INH, EN, TXD, and VSUP pin?

    Best,

    Chris

  • 0 in reply to Chris Ayoub
    TI__Expert 4060 points

    Hello Chris,
    TLIN1021 is applied as slave device. INH is connected with 10k pull-down means in Sleep Mode.

    Josef Warta said:

    Also Normal Mode is not possible because this needs EN=HIGH and this is due customer application fixed.

    -> This is related to function states after undervoltage. Device is in sleep, but how can this be when normal mode is not entered before.
    -> For Normal Mode: INH and EN = HIGH, see plot below this is not the case.


    CH2: VSUP (manual adjusted the voltage of the power supply)

    CH3: EN

    CH4: INH

  • 0 in reply to Chris Ayoub
    TI__Expert 4060 points

    Hello Chris,
    TLIN1021 is applied as slave device. INH is connected with 10k pull-down means in Sleep Mode.

    Josef Warta said:

    Also Normal Mode is not possible because this needs EN=HIGH and this is due customer application fixed.

    -> This is related to function states after undervoltage. Device is in sleep, but how can this be when normal mode is not entered before.
    -> For Normal Mode: INH and EN = HIGH, see plot below this is not the case.


    CH2: VSUP (manual adjusted the voltage of the power supply)

    CH3: EN

    CH4: INH

  • 0 in reply to Josef Warta
    TI__Genius 15345 points

    Hi Josef,

    Do you have a schematic? If you do not want to send it publicly you can email me at c-ayoub@ti.com. For your scope shot can you increase the V/Div on channel 2 so I can see when VSUP goes undervoltage and when it returns back to normal.

    Best,

    Chris

  • 0 in reply to Chris Ayoub
    TI__Expert 4060 points

    Let's continue it offline by e-mail. Many Thanks Josef