A 0.5-V R-MOSFET-C Filter Design Using Subthreshold R-MOSFET Resistors and OTAs With Cross-Forward Common-Mode Cancellation Technique

作者：Khumsat Phanumas^*; Worapishet Apisak

来源：IEEE Journal of Solid-State Circuits, 2012, 47(11): 2751-2762.

DOI：10.1109/JSSC.2012.2216708

• Active filters
• low voltage
• MOS resistors
• operational transconductance amplifiers (OTAs)
• R-MOSFET-C
• subthreshold
• tunable filters

A 0.5-V fully integrated R-MOSFET-C filter with low power, good linearity, and wide frequency tunability is demonstrated. It relies upon the operational transconductance amplifier using the cross-forward common-mode cancellation and the linear sub-threshold R-MOSFET resistor-both employ subthreshold operation of the transistors. A fifth-order Chebyshev low-pass filter using regular transistors with a 0.5-V threshold voltage in a 0.18-mu m triple-well CMOS process is implemented for a 0.5-V supply. The filter's bandwidth can be tuned from 91 to 268 kHz, which is almost a 3-to-1 tuning ratio. At a nominal bandwidth of 135 kHz automatically set by the on-chip PLL circuit, the dynamic range is at 61.0 dB for 1% total harmonic distortion, while the spurious-free dynamic range under two-tone signals is at 53.7 dB. The total current and power consumptions including bias circuits are 1.2 mA and 0.6 mW, respectively.

• 出版日期2012-11