What the 1.5 µA supply current means for your battery budget
The Renesas ISL21080CIH325Z-TK is a FGA™ series voltage reference that draws just 1.5 µA from the input rail. For a sensor node or portable instrument that spends most of its life in a low-power sleep state, that quiescent current is below the self-discharge floor of a typical CR2032 coin cell — the reference does not meaningfully shorten shelf life. It outputs a fixed 2.5 V with a ±0.3% initial tolerance and a 50 ppm/°C temperature coefficient, so the voltage a 12-bit ADC sees at 85 °C stays within roughly ±1 LSB of the room-temperature value — no external trim pot needed for most industrial-grade measurements.
Noise floor and ADC reference duty
For a 12-bit ADC with a 2.5 V reference, the peak-to-peak noise in the 0.1–10 Hz band represents about 5 LSBs of uncertainty — acceptable for a process-control loop but worth noting if the system targets 14-bit or higher resolution without averaging. The series-reference topology means the output is regulated from the input rail, not from a current through a resistor — the load regulation is inherently tighter than a shunt reference, and the output stays stable with the 7 mA maximum output current.