A 71-MNz CMOS IF-baseband strip for GSM

An intermediate-frequency (IF) baseband strip for a superheterodyne GSM rec eiver developed in a 0.25-mu m CMOS technology is presented. It contains a 71-MHz TF amplifier, programmable between -20 and +60 dB in 2-dB steps; a q uadrature demodulator; and two low-pass output filters for channel selectio n, Measurements show an overall maximum gain of 89 dB and a noise figure of 3.8 dB. Phase and amplitude mismatches of the demodulator are below 1 degr ees and 0.1 dB, respectively The high linearity required by the blocking an d intermodulating signals, which are not completely suppressed by the IF fi lter, has been achieved using 4.7 mA from the 2.5-V power supply.