A CNTFET universal mixed-mode biquad active filter in subthreshold region

摘要

This paper presents a new low-voltage and low-power mixed-mode universalactive filter, using only 12 carbon nanotube field effect transistors (CNTFETs) and2 grounded capacitors to improve the noise performance of the proposed circuit.Due to the use of subthreshold transistors biased at ±0.2 V supply voltage, thepower consumption of the proposed multi input-single output (MISO) filter is only850 nW at 19 MHz center frequency. On the other hand, relaxing from any matchingcomponents, the center frequency and quality factor of the proposed filter canbe tuned electronically with low sensitivity to the values of the active and passiveelements. Furthermore, the active chip area of the proposed filter is significantlyreduced to 0.047 μm~2, in 32 nm CNTFET technology. Therefore, as the HSPICEsimulation results show, the input referred noise values at 19 MHz are reduced to15.5 nV/HZ~(1/2)and 185 fA/HZ~(1/2)in voltage and current modes, respectively. It isalso shown that, by changing the number of nanotubes in the CNTFET structure, avery good power-frequency trade-off can be achieved for low-power GHzapplications.