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ADS131M04: Questions : (1)Input ratings at gain setting > 8, (2) 16bit output mode

Shinji Tsuji
Genius 14129 points
Part Number: ADS131M04

Hi team,

I

I have two questions for ADS131M04 as below.

 

1. When the gain of PGA >8, the recommended operating input voltage is AVDD-1.8V, while it is AVDD at PGA gain <4.

What is the negative impact when >AVDD-1.8V applied to the input at PGA gain =8?

From the absolute maximum ratings, input terminal is protected up to AVDD+0.3V, so there should be no damage, correct?

 

2. Regarding to the SPI 16 bit communication option(16bit data output not 24bit), does the device process 24bit internally and cutoff 8 bit at the final output stage?

I mean all the phase, gain calibration setting is done in 24bit? 

 regards,

  • 0
    TI__Mastermind 25020 points

    hello,

    1. A you are correct that the absolute max is up to AVDD+.3V, and thus the device would be protected if the input voltage is below that and should not be violated. But the recommended specs are different based on the gain, and the performance specs given are tested within the recommended specs provided. running the device beyond that could degrade device performance.  Also note that gain setting 4 is a divider for the enabling a pre charge buffer that affects the ADC input impedance.

    2. Correct, the device truncates, or cuts off the last 8 bits from the 24 to results in 16 bits.

    Regards

    Cynthia