Soo-Hwan Shin

A low phase noise and low power series coupled quadrature VCO using reconfigurable LC tank

To design a multi standard and a multi band transceiver, a quadrature voltage controlled oscillator (VCO), which has a wide tuning range, is essential, while providing low phase noise with low current consumption. In this paper, a dual band quadrature VCO in 0.18 mum CMOS process is presented. To accomplish dual band operation, reconfigurable LC tank is adopted. Series coupling transistors are attached to generate quadrature phase signal with low phase noise and low power consumption. To improve phase noise performance, a current source is eliminated, and a filter inductor at the common source node is added. The measured phase noises of low frequency mode and high frequency mode are -123.8 dBc/Hz and -115.06 dBc/Hz at 1 MHz offset frequency and FoM of -181.8 dB and -180.5 dB with 6.8 mW power consumption.

A Multistandard RF Front-End Using Varactor Controlled Tunable Interstage Matching Network

A multistandard RF front-end using a tunable interstage matching network is designed in 0.25 mum CMOS technology. It consists of a wideband LNA, interstage matching network, and a Gilbert-cell mixer. Tunability of the interstage matching can be obtained by a MOS varactor. It can change tuning frequency by controlling capacitance of varactor. Gain can be flattened over whole target band by the proposed interstage matching. Designed RF front-end has homogeneous performance from 1.8 to 2.4 GHz. It can be used for 3G wireless communications, mobile internet, and WLAN applications such as IEEE 802.11b/g

A CMOS Current-Reused Transceiver with Stacked LNA and Mixer for WPAN

A low power transceiver is designed in 0.25 mum CMOS technology. Designed transceiver is composed of CMOS PA and low-IF receiver architecture for high integration. To reduce the power dissipation, current-reused topology is used in Rx and up-conversion mixer. And, the simulated power consumption of PA is minimized by optimizing the size of power cells. The power consumptions are 31 mW and 69 mW for Rx and Tx paths, respectively, with 2.5 V supply voltage. Voltage conversion gain of designed receiver is varied from 11.5 to 27.5 dB. Output power is 14.7 dBm with 40 % of PAE at P1dB, and phase noise of QVCO is -122 dBc/Hz@1MHz. These performances are sufficient for WPAN applications such as Zig-Bee and Bluetooth

A Dual Band CMOS Quadrature VCO for Low Power and Low Phase Noise Application

To design a multi standard and a multi band transceiver, a quadrature voltage controlled oscillator (VCO), which has a wide tuning range, is essential, while providing low phase noise with low current consumption. In this paper, a dual band quadrature VCO in 0.18 mum CMOS process is presented. To accomplish dual band operation, reconfigurable LC tank is adopted. Series coupling transistors are attached to generate quadrature phase signal with low power consumption and low phase noise. To improve phase noise performance, current sources are eliminated and a filter inductor at the common source node is added. The measured phase noises of low frequency mode and high frequency mode are -101.81 dBc/Hz and -100.59 dBc/Hz at 10 kHz offset frequency; and -123.83 dBc/Hz and -115.06 dBc/Hz at 1 MHz offset frequency and figure of merit (FoM) at 1 MHz offset frequency of -181.8 dB and -180.5 dB with 4 mA current consumption with a 1.7 V supply.

A Low Phase Noise and Low Power Series Coupled Quadrature VCO for Dual Band Application

To design a multi standard and a multi band transceiver, a quadrature voltage controlled oscillator (VCO), which has a wide tuning range, is essential, while providing low phase noise with low current consumption. In this paper, a dual band quadrature VCO in 0.18 mum CMOS process is presented. To accomplish dual band operation, reconfigurable LC tank is adopted. Series coupling transistors are attached to generate quadrature phase signal with low phase noise and low power consumption. To improve phase noise performance, a filter inductor at the common source node is added to block draining second harmonic current to ground. The measured phase noises of low frequency mode and high frequency mode are -123.8 dBc/Hz and -115.06 dBc/Hz at 1 MHz offset frequency and figure of merit (FoM) of -181.8 dB and -180.5 dB with 4 mA current consumption with a 1.7 V supply.

A reconfigurable mixer with flexible matching network

To obtain reconfigurability of a mixer, the proposed mixer adopts a flexible matching network as a variable reactance transformer. By switching L and C of the matching network, input impedance of the mixer is varied in accordance with a wanted operation frequency. The performance of proposed mixer are simulated and verified by implementing a test board. The measured results of mixer satisfy present communication standards ranging from 2 GHz to 6 GHz.