A 2MHz CMOS Gm-C complex filter with on-chip automatic tuning for wireless sensor networks application

A g
_m
-C complex filter with on-chip automatic tuning for wireless sensor networks (WSN) is designed using 0.18¿m RF CMOS process. This filter is synthesized from a low-pass 5
^th
-order Chebyshev RLC ladder filter prototype by means of capacitors and fully balanced transconductors with extended linear range. A conventional phase-locked loop (PLL) is used to realize the on-chip automatic tuning for both center frequency and bandwidth control. The filter bandwidth is 2.4 MHz and is centered at 2 MHz. The image band rejection is higher than 63 dB while the ripple in the passband is less than 0.5 dB. The complete filter including on-chip tuning circuit consumes less than 5 mA with 1.8V single supply voltage.