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DRV10983: DRV10983 I2C AT 5V ?

user6011360
Prodigy 150 points
Part Number: DRV10983
Other Parts Discussed in Thread: PCA9306

https://e2e.ti.com/support/interface/f/138/t/827817

"Can you help to explain more details of DRV10983 I2C port ?"

The 0.6V ViL is the INPUT low threshold which our device will be below. I do not see any VoL specs (the one we care about) in the datasheet for the DRV device.

If I don't want to use the internal 3V3 LDO,

Should I connect another 3V3 LDO 's output to the V3P3 pin,

Or leave the V3P3 pint unconnected ?

  • 0
    TI__Mastermind 19720 points

    Hi,

    The DRV10983's I2C does not specify the VOL because the output is an open drain output. The DRV10983's open drain output will be equivalant to 7.34 Ohms when the DRV10983 is trying to send a 0. So this means that the VOL is dependent on the external pull up resistor. 

    If you are not going to use that V3P3 we still recommend that you connect a 1uF cap to GND.

    Regards,

    Michael 

  • 0 in reply to Michael.Walker
    TI__Mastermind 19720 points

    Also in the Datasheet we say that the I2C pins can only have a maximum of 4V on the pins. So the device cannot operate with a 5V I2C without damaging the part.

  • 0 in reply to Michael.Walker
    Prodigy 150 points

    @If you are not going to use that V3P3 we still recommend that you connect a 1uF cap to GND.

    Should I connect the outer LDO's out to V3P3 or NOT ?

  • 0 in reply to Michael.Walker
    Prodigy 150 points

    @Also in the Datasheet we say that the I2C pins can only have a maximum of 4V on the pins. So the device cannot operate with a 5V I2C without damaging the part.

    So,I am asking how to solve the problem,which level shifter should I use ?

  • 0 in reply to user6011360
    TI__Mastermind 19720 points

    Hi,

    "Should I connect the outer LDO's out to V3P3 or NOT ?"

    No, please do not connect the two.

    "So,I am asking how to solve the problem,which level shifter should I use ?"

    I am not very familiar with level shifters so I dont know which one to recommend. but any level shifter from 5V to 3.3V that has enough bandwidth for I2C should work. 

    Regards,

    Michael W

  • 0 in reply to Michael.Walker
    Prodigy 150 points

    @The DRV10983's I2C does not specify the VOL because the output is an open drain output. The DRV10983's open drain output will be equivalant to 7.34 Ohms when the DRV10983 is trying to send a 0. So this means that the VOL is dependent on the external pull up resistor. 

    @I am not very familiar with level shifters so I dont know which one to recommend. but any level shifter from 5V to 3.3V that has enough bandwidth for I2C should work. 

    Back to the question, I do not see any VoL specs (the one we care about) in the datasheet for the DRV device.

    Or how much current can SDA/SCL sink ?

  • 0 in reply to user6011360
    TI__Mastermind 19720 points

    Hi,

    I am not sure how much current that the SDA can sink, because there is always a resistor pull up that will limit the amount of current the SDA can sink. I looked around and here is a Level shifter that should work for you: PCA9306 http://www.ti.com/product/PCA9306

    Regards,

    Michael