A 0.68V 0.68mW 2.4GHz PLL for ultra-low power RF systems

A 2.4GHz PLL consuming 0.68mW has been implemented in 65nm LPCMOS for use in ultra-low power Bluetooth Low Energy (BLE) applications. VCO, charge pump and dynamic flip-flop design optimization allow low voltage operation at 0.68V, bringing down dynamic power. The integer-N PLL covers all BLE channels and has a phase noise of -110dBc/Hz at 1MHz offset. To extend operation to extremely low duty cycles, extensive power gating is applied to bring the leakage power down to 170pW.