An integrated zigbee transmitter and DC-DC converter on 0.18μm HV RF CMOS technology

A System-On-Chip (SOC) demonstrator integrating a low-noise IEEE 802.15.4 Transmitter and a DC-DC converter on a 0.18um High Voltage (HV) and RF CMOS process is presented in this paper. Noise isolation performance is critical to success of this type of SOC. A complete direct conversion transmitter was designed and various Quadrature VCO topologies were analyzed and compared based on the phase noise performance, device reliability, design robustness and image rejection. The final QVCO used in the transmitter has a FOM of 187dB, leading to an overall phase noise of -123dBc/Hz at 1MHz offset. The deep Nwell from HVCMOS process can be effectively used to provide isolation between the circuit blocks with measured results showing a sufficient noise isolation between the sensitive RF circuit and the switching 10MHz DC-DC converter.