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ADS131A04: Current on AVSS during Bipolar Supply Mode

Mark Philip Felipe
Genius 11070 points
Part Number: ADS131A04


Hi Team, we are hoping you could assist us with our customers inquiry. The datasheet specifies AVDD current only for the case when AVDD = 3.3V and AVSS = 0. How much current does AVSS source in bipolar supply mode?

Thank you very much.

Regards,

Mark Felipe

  • 0
    TI__Guru* 98295 points

    Mark,


    The current sunk by AVSS should be the same as the current sourced by AVDD, and the current is basically the same from unipolar supply of AVDD=3.3V to bipolar supply of ±2.5V for AVDD to AVSS. For the device operating in high-resolution mode, with fMOD at 4.096MHz, this would be about 4mA.

    As you mentioned, the electrical characteristics table on page 10 lists the power supply current to be 4mA at AVDD=3.3V. This is with high-resolution mode, with an fMOD at 4.096MHz. Further on in the datasheet, the typical characteristics curves show the AVDD current vs fMOD (see Figure 31 on page 20). For these currents, the AVDD to AVSS set at ±2.5V. Looking at the curve for fMOD=4.096MHz with high-resolution mode, the current is about 3.9mA (which is similar to the 4mA for AVDD=3.3V). For the analog current AVDD is the source, but AVSS is the return, so all AVDD current is sunk into AVSS. For DVDD, the return current is sunk into GND which is the digital ground.

    Note that there is some variation in the supply current. The values in the electrical characteristics table used from the typical to the max values for current show that the max is about 20% higher.


    Joseph Wu