Design Of Wideband Analog Baseband Core Circuits In Wireless Communication Transceiver System

In this paper,the analog baseband core circuits are designed for wideband wireless communication transceiver system,including programmable gain amplifier and channel selection filter.The programmable gain amplifier designed in this paper is based on the source degeneration resistance structure.By introducing the super source following technology,the contradiction between linearity and gain is alleviated,and the linearity of the circuit is improved.The bandwidth of the amplifier is expanded by introducing the source degeneration capacitor.Gain control is realized by programmable source degradation resistance,load resistance and bypass switch.Through comparative analysis,the optimal structure of programmable source degradation resistance,load resistance and the number of bypass switches are determined.The channel selection filter designed in this paper is a sixth-order Chebyshev active RC lowpass filter,which is realized by cascading three Sallen-Key second-order cells.The bandwidth of filter can be adjusted by switched capacitor array to meet the requirements of multi-mode and multifrequency applications.The double-input-pair fully differential operational amplifier is adopted to save power consumption.Miller compensation two amplification stages can provide higher openloop gain.The closed-loop common mode stability is improved by the active positive feedback load in the first stage.The values of passive components are designed reasonably to reduce the influence of high frequency feedthrough effect of Sallen-Key second-order cell.The programmable gain amplifier and channel selection filter are designed in 40 nm and 0.13?m CMOS process respectively.The post simulation results show that the programmable gain amplifier has a gain range of 0.5?20 dB with 0.5 dB/step,and a wide bandwidth of 2.1 GHz.The channel selection filter has a bandwidth of 138/163/201 MHz,and an adjacent channel rejection ratio greater than 42.3 dB.Compared with the literature in recent years,the performance of the analog baseband core circuits designed in this paper has certain advantages in many aspects.