Desensitized design of MOS low noise amplifiers by R/sub n/ minimization

We show that the minimization of device R/sub n/ allows us to simultaneously approach noise and input match in CMOS LNA designs in a topology independent fashion. The dependence of R/sub n/ on designer specifiable parameters is derived using a theoretical analysis of long channel (i.e square-law) devices. Experimental results are shown to confirm this dependence for short-channel devices. Using experimental data from a 0.18 /spl mu/m technology, we show that a low R/sub n/ design results in a /spl ges/2/spl times/ increase in the bandwidth over which an optimal noise figure can be obtained. The desensitization of the device with a low R/sub n/ provides a greater immunity to impedance mismatches, modeling errors and manufacturing variations.