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PGA302: I2C Addresses for multiple PGA302 ICs and more

Amr Wael
Intellectual 340 points
Part Number: PGA302
Other Parts Discussed in Thread: TEST2

Hello ,

I am designing a system where multiple PGA302 ICs are going to be used and I have multiple questions regarding the system.

1)  Is there an Address specific for each PGA302 ? Can I change the address for each one of them in order to communicate with each one using the same I2C bus ?

2) Are there any advantages for using OWI over I2C ? or I2C gonna let me access the same registers as OWI ?

3) What are the VinOH and VinOL for the I2C , can I use pull up  resistors to 3.3V although I am operating the IC using 5V ?

4) Can I leave unused pins such as the temperature input pins floating ?

5) Are there any external connections/Components required for the following pins (Test1 , Test2 , DACCAP) ?

6) in the application information it's written that the analog inputs should be between 0.2V and 4.2V , is this voltage range differential or single ended ?

7) What are the default Settings for the DAC registers and for the I2C ? 

Thank you very much in advance,

BR

Amr

R&D electronics Engineer

  • 0
    TI__Mastermind 24358 points

    Below are my answers for your questions:

    1)  Question: Is there an Address specific for each PGA302 ? Can I change the address for each one of them in order to communicate with each one using the same I2C bus ?  Answers: the I2C addresses are listed in table 5 (slave addresses).  This device has multiple addresses depending on the feature you want to communicate with.

    2) Are there any advantages for using OWI over I2C ? or I2C gonna let me access the same registers as OWI ?  One advantage of the OWI is that it can be connected through the power line.  Thus only a power and ground wire are required to communicate with the device.  This is a common approach used for communicating with PGA302.  I believe all the registers can be accessed by either i2c or OWI.  I will confirm ASAP.

    3) What are the VinOH and VinOL for the I2C , can I use pull up  resistors to 3.3V although I am operating the IC using 5V ?  I2C has standard logic thresholds.  This document covers I2C thresholds ( A Basic Guide to I2C).  It also covers the case you mention see page 25 and 26.  In short, it is not a good idea and you should use a level translator.

    4) Can I leave unused pins such as the temperature input pins floating ?  Yes.

    5) Are there any external connections/Components required for the following pins (Test1 , Test2 , DACCAP) ?  Test1 and Test2 may be useful for debug.  The evaluation module as an op amp buffer for these signals.  The DACCAP pin may be used as an input.  You may consider getting a copy of the evaluation module to help develop confidence in your solution and try experiments.  I think it is unlikely that these pins would be used in a final product as they are mainly for debug.

    6) in the application information it's written that the analog inputs should be between 0.2V and 4.2V , is this voltage range differential or single ended ?  This is the common mode range of the input.  Typically the differential input will be much smaller.   Keep both inputs within this limit.

    7) What are the default Settings for the DAC registers and for the I2C ?  Can you identify the specific register names?  I believe the register descriptions have the reset value in the table, but perhaps I am missing something.

    I hope this is helpful, Art Kay