A 2.7-V CMOS dual-mode baseband filter for PDC and WCDMA

摘要

A fifth-order analog CMOS RC-opamp baseband filter for a dual-modencellular phone receiver was designed with maximum component sharing innthe two modes, The filter meets the bandwidth specifications of both thenPDC and WCDMA standards, which represent the two extremes with respectnof the channel bandwidth. The total area of 4.8 mm2 wasnminimized by reducing the filter order from five to three in the PDCnmode, Also, the operational amplifiers with adjustable GBW were used tonminimize PDC-mode power consumption. The capacitance matrices were madenonly partially overlapping to reduce the resistance spread, The largestnresistors were implemented with T networks and the smallest capacitorsnwith series connections to extend the range of feasible passivencomponent values. The measured integrated input referred noise is 17nΜV and 47 ΜV in the PDC and WCDMA modes, respectively. The IIP3 isn+35 dBV in the WCDMA mode, and the circuit consumes 6.8 mW and 25.4 mWnin the PDC and WCDMA modes, respectively. The supply voltage is 2.7 V