A Novel Ultra-Low Power (ULP) Low Noise Amplifier using Differential Inductor Feedback

A novel ultra-low power (ULP) low noise amplifier (LNA) is proposed for low-power radio-frequency (RF) wireless radios. Using the differential inductor feedback structure along with the neutralizing capacitor, this configuration doubles the effective g_m of the input transistor, while canceling out the feed forward and LO leakage through the gate-drain capacitor. In this design, the input device is biased to operate in moderate inversion region to achieve microwatt power dissipation. Experimental results indicate a power dissipation of 100muW, a noise-figure (NF) of 3.9dB, and a forward gain of 16.8dB. The LNA also exhibits an 1IP3 of -11.2dBm and the input referred -1dB compression point of -21dBm. The circuit was fabricated in Jazz Semiconductor´s CMOS 0.18mum process and was powered up using a supply voltage of 1V. For comparison purpose, a ULP common-gate LNA was also designed and fabricated using the same process. Experimental results show that the proposed LNA exhibits higher gain, lower NF, and better linearity