The microphone input amplifier contains an automatic gain control (AGC) with a dynamic range of 40dB to generate an amplified and compressed signal for the ADC, which provides 14 Bit resolution at 8kHz sampling-rate. Furthermore all necessary power management is included such as bandgap reference and four voltage regulators. The two 2.9V regulators are used internally (analog and digital supply), but can also be used for external purposes as well. The third output is designed to supply the peripheral cells and an external digital core, and is programmable from 1.5V to 2.5V in 5 steps (default is 2.5V). They are all powered through a DCDC-Converter, which can work down to a voltage of 1V. So the whole chip can work from a single battery cell.