Electrical – Level shifter using LM324 Op Amp for ADC reading


I'm want to digitize an +/- 2.5 V signal using an ADS1256. Since the IC can't take negative voltages I designed a level shifter with a LM324 to translate the +/-2.5 V signal to 0 – 5 V but I was only able to translate up to 3.4 V since the LM324 isn't rail-to-rail. I also realized that the input signal (+/-2.5V) and output signal (0-3V) have different phases. I would like to know if I'm losing resolution or accuracy reading designing the level shifter with a LM324 instead of a rail-to-rail Op-Amp. The frequency range of the signal is 1 to 10 Hz.

The circuit I used is from this website: https://vidnyankendra.org/2017/02/17/level-shifter-using-op-amp/

enter image description here

enter image description here

Best Answer

You don't need an op amp. You can offset the signal with just a resistor network. You wouldn't use the full input range of the ADC but you don't care: it's a 24 bit ADC.