ADS131M08: Single ended operation

Just tie AINxN to ground and put your signal on AINxP.

Beware of common mode voltage constraints depending on your gain setting.

Hi Benjamin

Thanks. My single-ended signal range is from 0V to 3.3 V, say if I operate ADS131M08 with gain =1, what constraints can bother me? Could you please clarify this in detail? If we can directly connect single ended signal to AINxP then what is the need of ADC driver?

Regards

Deepak

With a gain of 1, you're not going to be bothered by common mode range issues.

A driver is not required with this ADC (although it can sometimes improve things anyway, depending on your signal source impedance).  SAR ADCs require a driver.

How about if the signal source impedance is tied to 50 ohms?

50 ohms will be fine.  I was confusing this ADC with a different one though - you can not measure 0-3V with this part; it's maximum range at gain 1 is 1.2V

Can you suggest multi-channel (as maximum as possible) simultaneous sampling ADC for mentioned requirements?

ADS131E08 seems like it would fit the bill.  Someone from TI may have a better suggestion.

Hi Deepak,

I modified my comments and suggestions as below, let me know if you have any further question, thanks.

ADS131M08 has a limited input range. ADS131E08 is a good solution for you, however if you tie the INxN to the GND, you will violate the PGA common-mode input range. The solution is to use a similar configuration as shown in Figure 58 (b) and Figure 59 (b) in the ADS131E08 datasheet, then the ADC will always compare your signal with the 2.5V DC on the INxN pin which is (AVDD+AVSS)/2 when your AVDD is 5V supply. Internal 2.4V or external voltage reference can be used in this case.

Best regards,

Dale