A low power 1.5GHz Gm-C filter with 0–40dB variable gain in 65-nm CMOS technology

Targeting to phase-array radar system, a 1.5GHz continuous-time fifth order Chebyshev Gm-C low-pass filter with unique gain adjustment is presented. This paper comes up with theoretical analysis and solutions to solve the problem existing in cascading design of high frequency biquad filters. Methods of low-power design and gain adjustment are also provided. The filter is designed with TSMC 65nm process. The post simulation results show that the filter realizes gain of 0-40dB with 1.5GHz cut-off frequency, the max gain-step smaller than 0.5dB. The IIP3 is 1dBm and NF is about 27dB. The chip without pads occupies 0.5 mm2 and consumes 11mw at a 1.2-V supply voltage.