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ADS7950 / questions of VBD ,GPIO

Ryuji
Guru 20090 points
Other Parts Discussed in Thread: ADS7950

Hello,
 
Could you please kindly let me know about ADS7950?
 
(1)
There is Logic level VOH as "Vdd-0.2V"  in the datasheet page 6.
But, I can't find information of Vdd.
Is this typo of the VBD? 
 
(2)
Please let me know pin connection of unused GPIO pins.
Should we connect to GND ? or No Connect ?
 
(3)
"Digital output to BGND" is "-0.3V to (+VA+0.3) V" in the datasheet page 4.
Is this correct ?
 
The VA is analog voltage.
I think that "Digital output" should be depended on  the VBD.
 
 
Best Regards,
Ryuji Asaka
 
 
  • 0
    Guru 20090 points
    Hello,
     
    Could I have the answer please?
    Our cusotmer request this information.
     
    If there is any problem , please let me know.
     
    Best Regards,
    Ryuji Asaka
  • 0 in reply to Ryuji
    TI__Guru 55466 points

    Hello Ryuji,

    Sorry for the delayed response; it appears we missed this post.

    1) The logic level VOH is in reference to the VBD supply.  This is a typographical error in the datasheet. 

    2) The GPIOs default to digital inputs when the device is powered up.  A recommendation is to connect the unused GPIO's to GND via a pull-down resistor (~10kOhm)

    I will verify/confirm with the design group regarding question (3), since the absolute maximum ratings are dependent on the internal ESD protection of the device.  I will get back with a response ASAP.

    Best Regards,

    Luis

  • 0 in reply to Luis Chioye
    Guru 20090 points
    Hello Luis san,
     
    Thank you for the information.
    I understood.
    I wait your response of (3).
     
    Best Regards,
    Ryuji Asaka
  • 0 in reply to Ryuji
    TI__Guru 55466 points

    Hello Ryuji,

    We are currently looking for confirmation into the absolute maximum spec for the digital output. We will get back to you ASAP.

    Best,

    Luis

  • 0 in reply to Luis Chioye
    TI__Guru 55466 points

    Hello Ryuji,

    Regarding the absolute maximum ratings table, the spec for the Digital output to BDGND should be with respect to the digital supply

    Best Regards,

    Luis