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Original question:

DS90UH947-Q1: Can DS90UH947-Q1 support V-by-one signal ?

DS90UH947-Q1: for 3.3V MCU, PDB, I2C , INTB and REM_INTB

PYTsai
Genius 11785 points
Part Number: DS90UH947-Q1


Hi 

We are using 3.3V MCU whose IO is 3.3V are below connection correct

1. Can i connect PDB pin directly to MCU's 3.3V I/O ?

2. Is it correct I2C connect directly to MCU's 3.3V I2C and also pull high to 3.3V?

3. is it correct INTB pull high to 3.3V

4. We do not use REM_INTB pin, can we left it open?  

  • 0
    TI__Guru** 103215 points

    Hello PYTsai,

    All of your statements are correct! Also make sure that you use 3.3V to supply VDDIO for the 947. 

    Best Regards,

    Casey 

  • 0 in reply to Casey McCrea
    TI__Genius 11785 points

    Hi Casey,

    Datasheet spec said VDDIO pin absolute Maximum rating is 2.5V. Would like to clarify do you mean VDDIO pin 16 and 33 connect to 3.3V supply? But this violate Datasheet's spec, would you help clarify?  

  • 0 in reply to PYTsai
    TI__Guru** 103215 points

    Hello PYTsai,

    I'm sorry that was an incorrect statement from my last response. The VDDIO 3.3V is for 948. For 947 please leave VDDIO at 1.8V but I2C can be pulled up to 3.3V. I will correct my previous answer too. 

    Best Regards,

    Casey 

  • 0 in reply to Casey McCrea
    TI__Genius 11785 points

    Hi Casey,

    No problem. 

    Since VDDIO is 1.8V, the PDB pin can only accept 1.8V. Can i do in this way to connect MCU's 3.3V GPIO to PDB pin to control it ? 

  • 0 in reply to PYTsai
    TI__Guru** 103215 points

    Hello PYTsai,

    These resistor values don't look right but if you were to select values that give 1.8V at the 947 when the GPIO is high then this should be acceptable. Just make sure to factor in the tolerance of the resistors, the tolerance of the PDB input leakage current, and the tolerance of the MCU voltage output levels. There could be a situation in which tolerance of those elements could cause the voltage to be incorrect for PDB s another option would be to use a FET/transistor-based circuit. 

    Best Regards,

    Casey