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ADS54J69: Connect two ADC on the same SPI port?

Art Mecina
Genius 16585 points
Part Number: ADS54J69

Hello Guys,

Good day.

Our just like to confirm if its okay to connect multiple ADCs on the same SPI port for this device?

Also, they want to know if the SDOUT pin is n a HiZ state when the enable signal is high?

Thanks for the confirmation!

Art

  • 0
    TI__Guru* 91947 points

    Art,

    You can drive multiple parts if you meet the current drive requirement of the devices in the chain.

    SDOUT is always active. It never gets tri-stated.

    Regards,

    Jim

  • 0 in reply to jim s
    TI__Genius 16585 points

    Thank you very much Jim!

    Our customer has clarification though. According to him if it never gets tri-stated, how can the high level been reached on SDOUT? If both output deliver the same current, the max level would be half the voltage level of DVDD. So in his mind, a write to the ADC works but never a reading.

    Below are his connections. The input signal SEN are routet seperatly to select ADC1 or ADC2.
    The input signals SCLK and SDIN are connectet together,  also the output signal SDOUT. 

    I might direct the customer on this ticket so that he could explain better his use case.

    Thanks!

    Art

  • 0 in reply to Art Mecina
    TI__Guru* 91947 points

    Art,

    You cannot short the two SDOUT's.  The SDOUT is driven even when SEN is high. This is why a write works and a read does not.

    Regards,

    Jim