This paper presents a 7 GHz differential current-reused voltage-controlled oscillator (CR-VCO) with low power consumption and low phase noise using 0.18-µm CMOS technology. The output power of this CR-VCO is enhanced by utilizing a trifilar-transformer-feedback technique. The lower phase noise is achieved by the more symmetric voltage swings resulting from the improved balance of switching current. At a 1.5-V DC supply voltage, the power dissipation is only 3.4 mW. The total tuning range is 1.4 GHz (17.9%) as the tuning voltage ranges from 0 V to 1.8 V. The optimum phase noise is around -117.3 dBc/Hz at a frequency offset of 1 MHz from the center frequency of 7.07 GHz. The corresponding output power is around -6.8 dBm. For the proposed CR-VCO, the calculated figures-of-merit, FOM and FOMT , are -188.9 and -193.9 dBc/Hz, respectively.

This paper presents the design of a driver amplifier (DA) for a cordless mouse application, operating at the 2.4 GHz ISM unlicensed band. The DA is a single-ended topology, and is composed of two stages: the first stage is a cascode amplifier to provide high gain and good input-output isolation, while the output stage is a simple common source amplifier that adopts a novel current reuse scheme to reduce the DC bias current by half. The DA implemented in a 0.18 µm CMOS process has a 16 dB gain at 2.4 GHz, and it can drive a 3 dBm to the antenna with an output stage drain efficiency of 31% and a power-added efficiency (PAE) of 20% while drawing 4.5 mA from a 1.8 V supply.

A new current reused quadrature voltage controlled oscillator (QVCO) is proposed and implemented using UMC 0.18 µm CMOS 1P6M process. The proposed circuit topology is made up two low voltage LC-tank VCOs, where the QVCO is obtained using the transformer coupling and current reuse technique. At 1.8 V supply voltage, the phase noise of the VCO is -117.13 dBc/Hz at 1 MHz offset frequency from the carrier frequency of 2.18 GHz, the core power consumption is 4.14 mW, the total power consumption is 6.48 mW and tuning range is about 160 MHz.