Other Parts Discussed in Thread: ADS1220,
Hello,
I'm looking for a solution to the following:
- Convert resistance from 4 thermistors (10k ohms at 25C, +/-0.1C accuracy, resistance can vary between 400 ohms to 40k ohms for the temperature range I'm interested in)
- Sample rate >80 sps / thermistor, so >320sps total
- Voltage resolution < 80uV
- Single supply (3.3V or 5V)
I'm planning to use a resistor divider for the R to V conversion (Vref - 0.1% resistor - thermistor - GND)
I looked at ADS124S06 and ADS1220 but the Vpp noise spec for ADS1220 seems kind of high for my application.
Also, it seems that I need to disable the PGA for these single ended conversions. Do I need to buffer the input signals in this case?
If I need external buffers (opamps) it seems more cost effective to use an external mux, and put the buffer between the MUX and the ADC rather than using four buffers. Is this correct?
Is there another solution (ADC/MUX/buffers) which is better suited for this application?
Thank you.