Green Bandpass Sigma Delta Modulator with Capacitive Feedforward Summation and Series-Peaking LNA Chip Design for Communication System Application

A continuous-time quadrature band-pass sigma-delta modulator consisting of a chain of integrators with a weighted capacitive feed-forward summation (CICFF) topology is presented for long-term evolution (LTE) network optimization and green application. The main advantage of the proposed modulator is that it adopts the weighted capacitor technology to save a feed-forward summation amplifier, and hence reduces power consumption. The chip was implemented in a TSMC 0.18-μm CMOS process. A low-noise amplifier for the reduction of components is used in this LNA. The integrated green single-stage of LNA uses series-peaking technology for low power requirement. With a 1.8-V supply voltage, a sampling rate of 200 MSamples/s and an input sinusoid of 1.0 dBm at 1 MHz, measured results have achieved a spurious-free dynamic range (SFDR) of 42 dB, a dynamic range (DR) of 56 dB, a peak SNDR of 57.86 dB, an effective number of bits (ENOB) of 9.3 bits over a 5-MHz signal bandwidth and a power dissipation of 21.8 mW for green computing and communication applications.