How bad can a $2.97 ADC be?
11 hours ago
- #Electronics
- #ADC
- #Embedded Systems
- Microcontroller ADCs are cheap and fast but have limited accuracy (8-9 ENOB).
- The ADS1115 is a dedicated ADC from TI offering 16-bit accuracy.
- ADS1115 features a dynamic range for finer small amplitude voltage measurements.
- Programmable gain amplifier allows full-scale range from ±6.144 V down to ±0.256 V.
- ADS1115 uses an internal voltage reference, unlike some microcontrollers requiring external references.
- Pricing discrepancy noted: $4 at Digikey vs. $0.60 on LCSC for ADS1115.
- Breakout boards from Amazon likely use cheaper LCSC parts.
- Testing revealed some ADS1115 units had deviations in data rate and measurement accuracy.
- One unit had a significantly faster data rate (300 samples/sec vs. expected 8-860).
- Measurement error observed (12 mV, 0.5% difference), but correctable with linear calibration.
- Cheap parts may be good copies or failed parts in the hobbyist supply chain.
- Upcoming test with a pricier ADS1115 version to compare performance.