A Low-Voltage CMOS Buffer for RF Applications Based on a Fully-Differential Voltage-Combiner

Part 20: Electronics: RF ApplicationsInternational audienceThis paper presents a new CMOS buffer circuit topology for radio-frequency (RF) applications based on a fully-differential voltage-combiner circuit, capable of operating at low-voltage. The proposed circuit uses a combination of common-source (CS) and common-drain (CD) devices. The simulation results show good levels of linearity and bandwidth. To improve total harmonic distortion (THD) a source degeneration technique is used. The proposed circuit has been designed in a 130nm logic CMOS technology and it achieves a simulated gain of 1.54 dB, a bandwidth of 1.14 GHz for a total power dissipation of 13.34 mW, when driving an RF active probe (with 0.8 pF in parallel with 200 kΩ)

Polyphase Comb Filter Based on Dispatching Input Bit-stream and Interlaying Multiplexer Techniques for Sigma-Delta ADCs

This paper describes a new design approach for implementing a Polyphase Comb Filter (PCF) based on dispatching input bit-stream and interlaying multiplexer techniques. In order to make our solution more energy efficient in comparison with prior art, we start with a detailed analysis of the drawbacks and advantages of the existing classical techniques. A new structure based on a novel SINC3 design is proposed. This new design uses a controller unit to activate one sub-filter in each specific time interval. As a consequence, no input registers and switches are required. Since this decimation filter is working with a single-bit output bit-stream, the required multiplication function can be simply done by using interlaying multiplexers (MUXs). By interlaying different levels of MUXs along with the navigation of the input bit stream we can easily emulate the multiplication operation. The implementation in a Xilinx Spartan3 FPGA demonstrates the feasibility and hardware efficiency of our solution . The proposed new filter architecture can be readily applicable to any Sigma-Delta (ΣΔ) ADC with a single-bit output stream and it requires a reduced number of adders and registers when compared with the state-of-the-art approaches