ADS1246EVM-PDK: Input Common-Mode Range of ADS1246

Dustin Lin

Part Number: ADS1246EVM-PDK

Hi,

Our customer is curious about the input common-mode range of ADS1246 and ADS124S08. Since for ADS1246, AVSS + 0.1V + [|VINMAX| • (Gain) / 2] < VAIN1, while for ADS124S08, AVSS + 0.15V + [|VINMAX| • (Gain − 1) / 2] < VAIN1. Why for ADS124S08, it should be gain-1, while for ADS1246, it's just gain?

ADS124S08:

Besides, is it calculated by the equation shown as the picture below? Does it mean that the output of the first-stage amplifier of the INA should be within the input common-mode voltage range of the INA? I'm quite confused.

Thank you so much for your help.

Best regards,

Dustin

over 4 years ago

0 Bryan Lizon86 over 4 years ago

TI__Mastermind 46231 points

Hi Dustin,

The best way to understand the relationship between the input signal and the absolute input voltage is to use the ADS124S08's calculator tool at the link below.

Here, you can input your settings to visualize how the input signal translates to the output signal, as well as if you are violating any of the absolute input voltage requirements as defined in that equation you mentioned in your post. I have included an image of this tab of the tool below as well.

Please review and let me know if you have any questions about this information.