9.4.3 Duty Cycling For Low Power

The noise performance of a ΔΣ ADC generally improves when lowering the output data rate because more samples of the internal modulator are averaged to yield one conversion result. In applications where power consumption is critical, the improved noise performance at low data rates may not be required. For these applications, the ADS111x support duty cycling that yield significant power savings by periodically requesting high data rate readings at an effectively lower data rate. For example, an ADS111x in power-down state with a data rate set to 860 SPS can be operated by a microcontroller that instructs a single-shot conversion every 125 ms (8 SPS). A conversion at 860 SPS only requires approximately 1.2 ms, so the ADS111x enter power-down state for the remaining 123.8 ms. In this configuration, the ADS111x consume approximately 1/100th the power that is otherwise consumed in continuous-conversion mode. The duty cycling rate is completely arbitrary and is defined by the master controller. The ADS111x offer lower data rates that do not implement duty cycling and also offer improved noise performance if required.