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TLIN1441-Q1: Questions for I/O pin

Shinji Tsuji
Genius 14119 points
Part Number: TLIN1441-Q1

Hi team,

I plan to use TLIN14413-Q1 (3.3V regulator version) in PIN mode and MCU which communicate with TLIN14413-Q1's VIO is 5.0V. 

Vcc=3.3V from TLIN14431-Q1 is supplied to the other components. 

Vlogic5 and Vlogic33 is separately specified in Recommended operating range while Logic_input/output is specified as 6V max in Absolute maximum ratings section.

1. Does it mean Input and Output has both 5V tolerance? or TLIN14431(3.3V regulator) only support I/O up to 3.465V?

2. nWDR/SDO pin input termination. 

It is described as below in the datasheet. In Pin mode(SPI is not used), nWDR/SDO has pull up or high impedance if not driven Low?

Since Vcc=3.3V and MCU IO=5.0V, I concern if there is internal pull up to 3.3V or not. 

3. WDI/SDI pin 

High level input is specified as 2.19V(min). Does this pin has 5V tolerance when Vcc=3.3V?

4. TXD pin 

Does this pin has 5V tolerance when Vcc=3.3V?

regards,

  • 0
    TI__Genius 15345 points

    Hi Shinji,

    Shinji Tsuji said:
    1. Does it mean Input and Output has both 5V tolerance? or TLIN14431(3.3V regulator) only support I/O up to 3.465V?

    The output I/O pins have 5V tolerance regardless of what LDO output you choose. As long as you stay within the absolute maximum ratings you can't permanently damage the device. The maximum voltage for any logic input or output pin is 6V. With most of the logic pins the VIH is around 2V it doesn't depend on VCC, so you would still be able to supply them with 5V logic.

    Shinji Tsuji said:
    2. nWDR/SDO pin input termination. 

    This is an output pin whether or not you use it in pin mode or SPI mode. As you stated there is a pull up to VCC. When the watchdog times out, this pin goes low for time of td and then release back to VCC. You have to make sure that your MCU can read a 3.3V signal but I would assume with most MCUs this would be fine.

    Shinji Tsuji said:
    3. WDI/SDI pin 

    As you said the VIH of this pin is 2.19V, so if you supply it with a 5V signal it will surely read that as a high and the pin will work fine.

    Shinji Tsuji said:
    4. TXD pin 

    The same thing is true with the TXD pin. The VIH is 2V so if you supply it with a 5V signal it will read that as a high and the pin will work fine.

    If this answered your questions don't forget to hit the button. If you have anymore questions let me know.

    Best,

    Chris

  • 0 in reply to Chris Ayoub
    TI__Genius 14119 points

    Hi Chris,

    Thank you. 

    I have further question on #2 nWDR/SDO pin. 

    When it is configured as nWDR, it is Open drain output and internally pulled up to Vcc=3.3V, correct?

    How much is the minimum VOH?

    Is it possible to externally pull up to 5V if MCU cannot receive 3.3V?

    regards,

  • 0 in reply to Shinji Tsuji
    TI__Genius 15345 points

    Shinji,

    Shinji Tsuji said:
    When it is configured as nWDR, it is Open drain output and internally pulled up to Vcc=3.3V, correct?

    That is correct.

    Shinji Tsuji said:
    How much is the minimum VOH?

    There technically is no minimum VOH, since you can pull it up to any voltage you want.

    Shinji Tsuji said:
    Is it possible to externally pull up to 5V if MCU cannot receive 3.3V?

    Yes you can pull it up to 5V.

    Best,

    Chris

  • 0 in reply to Chris Ayoub
    TI__Genius 14119 points

    How much is the internal pull up to Vcc? 

    In other words, I will use Vcc=3.3V version and communicate with 5V MCU, 

    In this case how much is the recommended pull up external resistance to 5V external supply

    to overcome this internal pull up?

    regards,

  • +1 in reply to Shinji Tsuji
    TI__Genius 15345 points

    I believe the pin is pulled up through an internal current source. You can use a 1K to 10K external pull up resistor. The stronger the resistor the better. 

    Best,

    Chris

  • 0 in reply to Chris Ayoub
    TI__Genius 14119 points

    Hi Chris,

    Thank you for your support.

    regards,