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101 results on '"Im, Donggu"'

7. A Sub-GHz/2.4 GHz Highly Selective Reconfigurable RF Front-End Employing an N-Path Complementary Balun-LNA and Linearized RF-to-BB Current-Reuse Mixer

Author

Kim, Dongmin, Kim, Dongmyeong, Llamas-Garro, Ignacio, and Im, Donggu

Abstract

A sub-GHz/2.4 GHz highly selective reconfigurable RF front-end employing $N$ -path complementary balun-LNA and linearized RF-to-BB current-reuse (CR) mixer is proposed to implement internet-of-things (IoT) devices supporting short- and long-range wireless connectivity technologies. The proposed balun-LNA is built based on an active feedback common-source (CS) amplifier with a common-gate common-source (CGCS) balun load. A complementary version is devised to avoid a severe voltage drop across the resistor load attaining sufficiently high gain and increased effective transconductance without additional current consumption. In addition, an 8-path notch filter is added at a feedback path to improve LNA selectivity in sub-GHz. At 2.4 GHz, an inductive source degenerated LNA (ISDLNA) is used to achieve low noise figure (NF). The proposed RF-to-BB current-reuse mixer employed a second-order-intermodulation (IM2) injection technique for the linearization of the RF front-end. The IM2 injection technique improves linearity by generating the in-phase fundamental signal and out-of-phase third-order-intermodulation (IM3) signal, compared to the passive mixer output. The auxiliary path for the linearization is designed to consume ultra-low power by employing a newly proposed current-reuse-based differential IM2 generator, passive multiplier, and current-steering-based summing stage. As a result, the proposed RF-to-BB CR mixer alleviates the loading effect for the balun-LNA while achieving better gain, NF, and linearity with low power consumption. In measurement, the proposed front-end achieved the conversion gain of 50.5 ~ 44.4 dB and 39.4 dB and double-sideband noise figure (NFDSB) of 4.4 ~ 5.7 dB and 5.3 dB, respectively, in sub-GHz and 2.4 GHz. It also achieved in-band and out-of-band input-referred third-order intercept point (IIP3) from −18.0 to −15.2 dBm and from −0.4 to −2.6 dBm in sub-GHz and, the in-band IIP3 of −15.0 dBm at 2.4 GHz. The chip area of the proposed RF front-end core was less than 1.3 mm2 excluding the measurement buffer and I/O PADs.

Published
2024
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46. A 50–450 MHz Tunable RF Biquad Filter Based on a Wideband Source Follower With > 26 dBm IIP3, +12 dBm P1dB, and 15 dB Noise Figure.

Author

Lee, In-Young, Im, Donggu, Ko, Jinho, and Lee, Sang-Gug

Subjects
RADIO frequency, BROADBAND communication systems, BIQUADRATIC filters, BANDWIDTHS, OPERATIONAL amplifiers
Abstract

This paper reports a source follower-based active RC filter topology for RF front-ends in wideband systems. In the proposed active RC filter, the noise figure and bandwidth are improved through adopting the proposed sub-1 \Omega Z out source follower, which replaces the conventional operational amplifier-based unity gain buffer and through simply changing its location in the filter. Applying the proposed scheme to the conventional Sallen–Key filter also improves the stopband rejection performance. Furthermore, the proposed filter topology ultimately suppresses the DC offset voltage and flicker noise of the unity gain buffer, which is the only active circuit in the filter. The proposed biquad filter is implemented in 0.18 \mu\m CMOS and the measurements exhibit >26 dBm IIP3, +12 dBm input P 1dB, and <15 dB noise figure over 50–450 MHz of a 6 bit tunable frequency range. The proposed biquad filter consumes 14 mA from a 1.8 V supply and the chip occupies 1000\times500 \mu \m ^2. [ABSTRACT FROM PUBLISHER]

Published
2015
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