Tool/software:
Hello support team,
I've just got a ADS122U04EVM and want to test it.
I followed chapter 5.1.4 of SBAU288 (JP6: off, JP9: 2-3, JP10 on, JP13: 2-3)
I supplied 3.3V to JP6, + at IN0 and - at COM
I measured also directly between AIN0 and AIN2, it's about 0.52V (correct after voltage divider)
However, I get only 890800 ADC value, corresponds to 0.26V with the evaluation software.
Could you please help me with this?
Thank you and regards.
Quy
Hi Quy Nguyen,
However, I get only 890800 ADC value, corresponds to 0.26V with the evaluation software.
With your setting of AVDD (5V) as the reference, an output code of 890800 (decimal) corresponds to ~0.53V, which matches your measurement:
I measured also directly between AIN0 and AIN2, it's about 0.52V (correct after voltage divider)
The following equation from section 8.5.2 of the data sheet shows how to convert between output code and voltage value:
With a VREF of 5V (AVDD), and gain of 1, one LSB = (2* 5V / 1) / 2^24.
1 LSB = ~0.596uV
multiplying the voltage value of 1LSB times your output code of 890800 = (0.596uV * 890800) = ~0.5309V
This is the correct result.
However, I get only 890800 ADC value, corresponds to 0.26V with the evaluation software.
Where does the statement that it corresponds to 0.26V come from?
Best Regards,
Angel
