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ADS1278-SP: VREEFP Power Sequence

saman kholdebarin
Prodigy 40 points

Part Number: ADS1278-SP

Tool/software:

Hello,

Is there a sequencing required for VREFP pin if external source is used (2.5V dedicated precision reference source).

In what order should power on VREFP come up in reference to DVDD and AVDD?

Thanks,

Saman

  • 0
    TI__Guru 50290 points

    Hello Saman,

    VREFP should come up after AVDD supply has powered-up in order to stay within datasheet ABS MAX specs.  It can ramp at the same time as long as the VREFP voltage never exceeds the AVDD voltage by more the 0.3V

    All inputs, including analog inputs, reference inputs, and digital inputs, must not exceed the datasheet ABS MAX values during power-up, or you could possibly damage the device or get it into a non-functioning mode that requires another power cycle to correct.

    Figure 85 in the ADS1278-SP datasheet specifies the preferred startup sequence.  However, the device will not be damaged if this sequence is not followed.  As long as the /SYNC pin is asserted after device power-on and first data appear, then you will get correct operation.

    Regards,
    Keith Nicholas
    Precision ADC Applications