Sang-Sun Yoo

A Low Power Current-reused CMOS RF Front-end with Stacked LNA and Mixer

A low power variable gain RF front-end is designed and fabricated in 0.25 mum CMOS technology. Power consumption can be reduced by sharing current between cascode LNA and mixer. The power consumption of designed RF front-end is 11.3 mW with 2.5 V supply voltage. Also, gain of the RF front-end is varied from 14.5 to 30.5 dB by changing the load impedance of LNA

A Compact Dualband LNA Using Self-matched Capacitor

A designed LNA can support the dualband; 2.3~2.5 GHz and 5.1~5.9 GHz. Switched inductor and switched capacitor is adopted for frequency selection. In switched inductor and capacitor matching network, the optimizing techniques to minimize the insertion loss are explained and self-matched capacitor is proposed for easy flexible impedance and noise matching in the various frequency bands. As using switched inductor and capacitor matching network, a designed LNA can support IEEE 802.11a/b/g in 2.4 GHz and 5.2 GHz. The performances of LNA are comparable with those of LNA for single standard due to self-matched capacitor and optimized switched inductor matching network. The dualband LNA is designed with small the size (0.5 mm2) by reducing the number of inductors.

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

Optimazation of Switchable Inductor and Application to Reconfigurable LNA with Self-matched Capacitor

The matching methods for multiband operation are studied and analyzed. Then, switched inductor matching method is adopted because of its prominent characteristic about frequency selection. In switched inductor matching network, the optimizing techniques to minimize the insertion loss are studied and self-matched capacitor is proposed for easy flexible impedance and noise matching in various frequency bands. As using switched inductor matching network, a designed LNA can support IEEE 802.11a/b/g in 2.4 GHz and 5.2 GHz. The performances of LNA are comparable with those of LNA for only single standard due to self-matched capacitor and optimized switched inductor matching network.

A CMOS multi-standard mixer for WCDMA, Wi-Bro and 802.11a/b/g

A multi-standard direct-conversion mixer for WCDMA, WiBro and 802.11a/b/g is designed in 0.18 /spl mu/m CMOS technology. The mixer can be used in RF receiver for multi-standard because of switched inductor matching network. Frequency band selection can be done by turning on or off the switch transistor in the matching network. Accordingly, designed mixer is able to keep measured return loss below -13 dB through 2.1/spl sim/2.5 GHz and 5.15/spl sim/5.825 GHz bands. The following results are achieved: 14/spl sim/16 dB voltage conversion gain, 8.7/spl sim/9.7 dB NF, -8/spl sim/-3.7 dBm IIP3 with 8.8 mW power consumption in 2.1/spl sim/2.5 GHz band; also, 8.3/spl sim/10 dB voltage conversion gain, 12/spl sim/13.4 dB NF and 0.1/spl sim/1.7 dBm IIP3 with same power consumption are obtained in 5.1/spl sim/5.8 GHz band,.