A 2.4-GHz ZigBee Transmitter Using a Function-Reuse Class-F DCO-PA and an ADPLL Achieving 22.6% (14.5%) System Efficiency at 6-dBm (0-dBm) Pout.

This paper describes a sub-1-V 2.4-GHz ZigBee transmitter (TX) with scalable output power (Pout) and system efficiency. It features a function-reuse class-F topology unifying the digital-controlled oscillator (DCO) and power amplifier (PA), designated as DCO-PA. Unlike the existing current-reuse topologies that rely on transistor stacking, here the power consumption of the DCO and PA-driver is abs...