ADP3450 adjusting voltage range of acquisition

[Mohammad Alsmadi]

Hello, 

The resolution for the ADP345 is 14-bit with +/-25V (50V difference) input range. Is it possible to adjust the input voltage range (reduce it) to achieve better voltage sensing resolution?

Thanks, 

[attila]

Hi @Mohammad Alsmadi

For 1X input set the channel Range to 200mV/div or lower, for 10X 2V/div or lower...

[Mohammad Alsmadi]

Thank you @attila, 

The voltage range that I am looking to sense is ~4V. If I understand correctly, I should scale the signal down by 10 times using 0.1X attenuation and a range less than or equal to 200mV so that I can keep the resolution at 130uV, correct?  

 

 

 

Edited December 11, 2023 by Mohammad Alsmadi

[attila]

Hi @Mohammad Alsmadi

0.1X attenuation would require amplifying the input signal by 10.
10X attenuation is for 10X probe (1:10 probe in 10X position) which reduces the input signal from probe to the device by 10 and the software scales is back by 10 to represent how it is on the tip of the probe. With 10X the low range is up to 2V/div (1X=0.2V/div) and the ADC resolution ~1.3mV (1X=0.13mV). The 10X probe needs to be tuned. The 10 reduces the probe capacitance, increases the bandwidth.
Depending on your requirements you could use AC coupling.
For repetitive signals you could use the Time/Average.
 

[Mohammad Alsmadi]

Thank you @attila,

Just to confirm, if I use oversampling, the resolution is 16 bits. Then, the ADC resolution for the 50V range is around 0.7mV?