A 1.3-V 5-mW fully integrated tunable bandpass filter at 2.1 GHz in 0.35-m CMOS

ment LC bandpass biquad programmable in, , and peak gain is implemented in 0.35- m standard CMOS technology. The filter uses a resonator built with spiral inductors and inversion-mode pMOS capacitors that provide frequency tuning. The tuning is through an adjustable negative-conductance generator, whereas the peak gain is tuned through an input stage. Noise and non-linearity analyses presented demonstrate the design tradeoffs in-volved. Measured frequency tuning range around 2.1 GHz is 13%. Spiral inductors with of 2 at 2.1 GHz limit the spurious-free dynamic range (SFDR) at 31–34 dB within the frequency tuning range. Measurements show that the peak gain can be tuned within a range of around two octaves. The filter sinks 4 mA from a 1.3-V supply providing a of 40 at 2.19 GHz with a 1-dB compression point dynamic range of 35 dB. The circuit operates with supply voltages ranging from 1.2 to 3 V. The silicon area is 0.1 mm2. Index Terms—LC bandpass filter, radio-frequency (RF) CMOS, tunable filter. I