A CMOS continuous-time Gm-C filter and programmable gain amplifier for WPAN receivers

This paper describes a low-voltage and low-power channel selection analog front end with continuous-time low pass filters and highly linear programmable-gain amplifier(PGA). The filters were realized as balanced Gm-C biquadratic filters to achieve low current consumption. High linearity and constant wide bandwidth are achieved by using a new transconductance(Gm) cell. The POA has a voltage gain varying from 0 to 65 dB, while maintaining a constant bandwidth. A filter tuning circuit that requires an accurate time base but no external components is presented. Both the filter and PGA were implemented in a 0.18um 1P6M n-well CMOS process. They consume 3.2 mW from a 1.8 V power supply and occupy an area of 0.19 mm².

1. Introduction

The demand for low-cost low-power wireless tranceivers operating in the Wireless Personal Area Network(WPAN) has led to extensive research on RF circuit design[1]. Particularly, since one of the characteristics of such a WPAN transceiver is that it has wider channel spacing than the BW channel has, its filter attenuation requirement is lower than other wireless communication specifications[2]. Thus, it is possible to use a filter of a lower order, and it necessarily requires characteristics of low power consumption and low cost. This paper suggests that the Analog Front End in transceiver is relevant to this WPAN.