In ECA-series potentiostats, we use four high-resolution analog-to-digital converters in interleaved mode to maximise both sampling rate and signal-to-noise ratio.
This allows transients and currents down to the picoamp range to be resolved, even on top of a large background current.
In the figure above, 10 pA current steps are resolved over a 19.6 nA background. This matters for biosensor development, high-impedance materials, and low-level current detection in the presence of leakage.