ADS1256: How to Properly Design the ADS1256 Circuit and Choose Decoupling Capacitors?

Hi LEO_0916,

Some thoughts about your schematic:

• You should consider adding pull-ups on RESET and PWDN to DVDD to ensure that the ADC is in a known state at powerup
• The ADS1256 VREF inputs are not buffered. You should consider adding a buffer to the output of the REF5025, or use a buffered reference such as REF6025
• You do not need all of the capacitors on the VREF inputs. 100nF across the inputs should be sufficient
• The REF5025 recommends a 1uF cap between the NR pin and ground, as well as an optional ESR resistor + cap between VOUT and ground

-Bryan

Hi LEO_0916,

This looks like you made all of the changes we recommended, so that is a good start

Regarding your question: even if you do not connect anything to the SYNC/PWDN pin, you can still issue the SYNC command to synchronize the conversion. So that functionality is still available to you, just by command and not using the pin.

-Bryan