Low-frequency noise properties of dynamic-threshold (DT) MOSFET's

This paper shows that MOSFET operated in dynamic-threshold (DT) mode [1] (V -body = V-gate) is more suitable for low-noise RF/analog applications than those operated in conventional mode (V-body = V-source). Detailed low-frequ ency noise properties of these two modes of device operation were compared for 0.31-mu m gate MOSFET's, in which NMOS's are surface-channel devices (S .C.) and PMOS's are buried-channel (B.C.) devices. Experimental data show t hat when the devices are biased at same transconductance, the low-frequency noise in DT mode is 30 times lower (at g(m) = 2.2 x 10(-3) S) than that in the conventional mode (conventional mode) for the B.C. devices and ten tim es (at g(m) = 2.9 x 10(-3) S) lower for the S.C. devices.