860 SPS sigma-delta — what 16 bits cost in bandwidth
The ADS1118IDGST is a Texas Instruments 16-bit sigma-delta ADC that samples at 860 SPS. That 860 SPS is the output data rate — the modulator runs faster and the digital filter decimates to 860. For a sigma-delta, the effective number of bits (ENOB) climbs as you drop the data rate; at 860 SPS you get the full 16-bit resolution, but if you need 16-bit settling on a multiplexed channel, budget the filter settling time between mux switches.
MUX-PGA-ADC chain — no external signal conditioning needed
The front-end is a 2-channel differential or 4-channel single-ended mux feeding a programmable gain amplifier (PGA) and then the sigma-delta modulator. The PGA allows full-scale ranges from ±256 mV to ±6.144 V, letting you digitise small sensor outputs (thermocouples, strain gauges) without an external op-amp. The on-chip temperature sensor uses the same ADC core and reports the die temperature — useful for cold-junction compensation or ambient monitoring.
The internal voltage reference (2.048 V nominal) eliminates the external reference IC, saving board space and BOM cost.
Active production — sourced per BOM quantity
No official second-source or pin-compatible alternate is listed in the TI documentation; the ADS1118 family shares the same base die but package and temperature grade vary by suffix.