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ADS124S06: DVDD supply current and how to make DVDD

Oba
Genius 17355 points
Part Number: ADS124S06
Other Parts Discussed in Thread: TPS797

Hello,

 

My customer has a question for ADS124S06.

Due to their board space limitation, they want to use the simplest way to make 3.3V from 5V for DVDD (only DVDD, not including IOVDD. IOVDD=5V in this case).

They think the simplest way is using just a resistor divider.

The datasheet shows only supply current data for DVDD+IOVDD without SPI communication.

 

How much current is required for only DVDD including SPI communication case?

Is using just a resistor divider from 5V to 3.3V acceptable idea for this device to DVDD?

Or should they absolutely use a LDO or a shunt regulator?

 

Regards,
Oba

  • +1
    TI__Guru** 113765 points

    Hi Oba,

    It is difficult to say which approach will work as all validation testing is done using a stable source with low output impedance.  Using a resistor divider is definitely not a good approach as DVDD is the main core for the digital.  The current draw will be very dynamic and a brownout condition could easily occur.

    My recommendation would be to use an LDO over a shunt regulator.  I do not support the power products, but I do know they have LDOs that are packaged quite small and approach the size of shunt regulator (TPS797).

    Best regards,

    Bob B