Hi ,
I use ADS1256 and have some problems about input and reference voltages.
1-) Can I apply negative voltage source to VREF ?
2-) For datasheet, if I enable buffer on , AIN voltage is AGND to AVDD - 2 V . How can I apply negative voltage ( example : -10 mV) to AIN ?
Hi Nuri,
As you can see from the ADS1256's datasheet, a negative reference voltage is not allowed. The differential reference voltage (VREF) must be between 0.5V and 2.6V, while the negative reference input (VREFN) must stay at or above AGND as shown.
In order to apply a negative voltage to the ADS1256, you would need some sort of level shifting circuit e.g. an inverting amplifier, since the ADS1256 cannot accept signals below GND.
What is the signal range you are trying to measure?
-Bryan
