Highly linear receiver RF front-end adopting MOSFET transconductance linearization by linearly superposing several common-source FET transistors in parallel (multiple gated transistor, or MGTR), combined with some additional circuit techniques are reported. In MGTR circuitry, linearity is improved by using transconductance linearization which can be achieved by canceling the negative peak value of g/sub m/'' of the main transistor with the positive one in the auxiliary transistor having a different size and gate drive combined in parallel. This enhancement, however, is limited by the distortion originated from the combined influence of g/sub m/' and harmonic feedback, which can greatly be reduced by the cascoding MGTR output for the amplifier and by the tuned load for the mixer. Experimental results designed using the above techniques show IIP/sub 3/ improvements at given power consumption by as much as 10 dB for CMOS low-noise amplifier at 900 MHz and 7 dB for Gilbert cell mixer at 2.4 GHz without sacrificing other features such as gain and noise figure.

Highly linear receiver front-end adopting MOSFET transconductance linearization by multiple gated transistors

A transformer-feedback voltage-controlled oscillator (TF-VCO) is proposed to achieve low-phase-noise and low-power designs even at a supply below the threshold voltage. The advantages of the proposed TF-VCO are described together with its detailed analysis and its cyclo-stationary characteristic. Two prototypes using the proposed TF-VCO techniques are demonstrated in a standard 0.18-/spl mu/m CMOS process. The first design using two single-ended transformers is operated at 1.4 GHz at a 0.35-V supply using PMOS transistors whose threshold voltage is around 0.52 V. The power consumption is 1.46 mW while the measured phase noise is -128.6 dBc/Hz at 1-MHz frequency offset. Using an optimum differential transformer to maximize quality factor and to minimize the chip area, the second design is operated at 3.8 GHz at a 0.5-V supply with power consumption of 570 /spl mu/W and a measured phase noise of -119 dBc/Hz at 1-MHz frequency offset. The figures of merits are comparable or better to that of other state-of-the-art VCO designs operating at much higher supply voltage.

Ultra-low-Voltage high-performance CMOS VCOs using transformer feedback

A single-chip 2.4-GHz CMOS radio transceiver with integrated baseband processing according to the IEEE 802.15.4 standard is presented. The transceiver consumes 14.7 mA in receive mode and 15.7 mA in transmit mode. The receiver uses a low-IF topology for high sensitivity and low power consumption, and achieves -101 dBm sensitivity for 1% packet error rate. The transmitter topology is based on a PLL direct-modulation scheme. Optimizations of architecture and circuit design level in order to reduce the transceiver power consumption are described. Special attention is paid to the RF front-end design which consumes 2.4mA in receive mode and features bidirectional RF pins. The 5.77 mm2 chip is implemented in a standard 0.18-mum CMOS technology. The transmitter delivers +3 dBm into the 100-Omega differential antenna port

A Fully Integrated 2.4-GHz IEEE 802.15.4-Compliant Transceiver for ZigBee™ Applications

Wireless sensor nodes are autonomous devices incorporating sensing, power, computation, and communication into one system. Applications for large scale networks of these nodes are presented in the context of their impact on the hardware design. The demand for low unit cost and multiyear lifetimes, combined with progress in CMOS and MEMS processing, are driving development of SoC solutions for sensor nodes at the cubic centimeter scale with a minimum number of off-chip components. Here, the feasibility of a complete, cubic millimeter scale, single-chip sensor node is explored by examining practical limits on process integration and energetic cost of short-range RF communication. Autonomous cubic millimeter nodes appear within reach, but process complexity and substantial sacrifices in performance involved with a true single-chip solution establish a tradeoff between integration and assembly.

SoC Issues for RF Smart Dust

Transceiver architecture selection: Review, state-of-the-art survey and case study

An experimental 2.4-GHz CMOS radio composed of RF and digital circuits for the low-power and low-rate preliminary IEEE802.15.4 WPAN is reported, consuming 21 mW in receive mode and 30 mW in transmit mode. The RF design focus is to maximize linearity for a given power consumption using linearization methods which lead an order of magnitude improvement in LNA/mixer IIP3/power performance. Chip-on-PCB technology allows implementation of a coin-sized radio at very low cost, which also provides 3 dBi gain patch antenna and high Q (>50) inductors.

Seokjong Park

Papers

An experimental coin-sized radio for extremely low-power WPAN (IEEE 802.15.4) application at 2.4 GHz