I'm going to be designing a discrete delta-sigma ADC to be built on a PCB. I think I understand the basic concept, but I will need to order components fairly soon. Here's my problem: while I have learned about op-amp/comparator parameters, I don't know which parameters I should prioritize when choosing parts for my application.
- Since the op-amp is configured as an integrator, input offset voltage/current could be a major problem.
- I'm currently considering using a TL07x-series op-amp.
- Would the DC offsets of this device be problematic?
- When choosing comparators, should I be more concerned about propagation delay, hysteresis, or input offsets? I am currently considering the LM393, KA319, and the LM311.
- What other considerations should I take into account? Are my concerns even warranted, considering that my goal is not a high-performance device?
- I will be manually soldering the PCB, meaning that I would prefer DIP packages, though I can work with SOIC.
- My goal is to get a working design, it does not need to have high accuracy.
- The device does not need to operate at high frequencies, though something that can work at (44.1ksps or higher) would be nice.
Summary: I am wondering if the input offsets introduced by both the op-amp and the comparator at the input stage will cause the integrator to drift significantly, or if the capacitor will be charged/discharged quickly enough for errors introduced from DC offsets to be negligible.