A low-voltage low-power log-domain band-pass filter

In this paper, a log domain band-pass filter based on the MOSFET square law is proposed. This approach demonstrates that the center frequency ω₀ of band-pass filter is not only attainable at megahertz frequencies but also tunable electronically. In addition, constructed by low-voltage current-mode square-root circuit blocks, current mirrors and capacitors, the proposed band-pass log filter can be operated at 2.5 V supply voltage. The proposed circuit has been fabricated in 0.25 μm CMOS technology, and the measured results show that the proposed circuit has the merits of high frequency operation, tunability, and low power supply voltage operation.