An ultra low power, low voltage CMOS squarer circuit for non-coherent IR-UWB receivers

This paper presents an ultra low power, low voltage, high gain squarer circuit for use in non-coherent impulse radio ultra wideband (IR-UWB) receivers. The proposed squaring function is implemented based on the intrinsic CMOS transistor characteristics in the sub-threshold region, where the second-order derivative of the drain current is maximized. Additionally, a capacitor cross-coupling g_m boosting technique is exploited to increase the conversion gain of the squarer. Utilizing the aforementioned schemes, a low power and high gain squarer is realized in a TSMC 90nm CMOS technology. Simulation results demonstrate that the proposed squarer covers the UWB bandwidth and provides 16dB of RMS conversion gain at the input signal level of 100mV, while drawing only 320μA from a 0.5V power supply.