1.0 V-0.18 m CMOS Tunable Low Pass Filters with 73 dB DR for On-Chip Sensing Acquisition Systems

This paper presents a new approach based on the use of a Current Steering (CS) technique for the design of fully integrated G(m)-C Low Pass Filters (LPF) with sub-Hz to kHz tunable cut-off frequencies and an enhanced power-area-dynamic range trade-off. The proposed approach has been experimentally validated by two different first-order single-ended LPFs designed in a 0.18 mu m CMOS technology powered by a 1.0 V single supply: a folded-OTA based LPF and a mirrored-OTA based LPF. The first one exhibits a constant power consumption of 180 nW at 100 nA bias current with an active area of 0.00135 mm(2) and a tunable cutoff frequency that spans over 4 orders of magnitude (similar to 100 mHz-152 Hz @ C-L = 50 pF) preserving dynamic figures greater than 78 dB. The second one exhibits a power consumption of 1.75 mu W at 500 nA with an active area of 0.0137 mm(2) and a tunable cutoff frequency that spans over 5 orders of magnitude (similar to 80 mHz-similar to 1.2 kHz @ C-L = 50 pF) preserving a dynamic range greater than 73 dB. Compared with previously reported filters, this proposal is a competitive solution while satisfying the low-voltage low-power on-chip constraints, becoming a preferable choice for general-purpose reconfigurable front-end sensor interfaces.