A 1-V 2-mW Active-RC Low-Pass Filter With Programmable Cutoff Frequency in 22 nm CMOS

A 5th-order Chebyshev-I active-RC analog low-pass filter (LPF) with programmable cutoff frequency (f
0
) was fabricated in a 22nm ultra-low-leakage CMOS process. The proposed filter is targeted to application scenarios such as low-voltage and low-power wireless communication systems with different base-band signal bandwidths. The cutoff frequency reconfiguration of the filter is realized in a novel way by switched-resistors with proportional resistance values. A two-stage fully differential operational amplifier (op-amp) with feed-forward compensation (FFC) and common-mode feedback (CMFB) blocks was implemented to meet the stringent filter’s requirements. The LPF features f
0
-programmability of 5/10/ 20/30/40/50 MHz. The compact LPF tape-out layout (with pads) occupies $865\times 466\mu \mathrm{m}^{2}$. As the simulation results show, the LPF’s averaged input noise is $43-\mathrm{nV}/\sqrt{\mathrm{Hz}}$, and the in-band third-order input intercept point is 13.4 dBm while consuming 2 mA from a 1 V supply.