Ultra-low power 3.5–4.5GHz FM-UWB transmitter

This paper presents a novel ultra-low power FM-UWB transmitter implemented in 130nm CMOS process. The transmitter operates in the range of 3.5-4.5GHz with 4GHz RF carrier frequency. The transmitter can accept input data rates up to 250kbps. It consists of a relaxation oscillator to generate the subcarrier signal and a VCO for RF carrier generation. The center frequency of the VCO is periodically calibrated by an integer-N phase-locked loop (PLL). The PLL takes only 300ns to complete the calibration. The simulated VCO phase noise is - 79dBc/Hz at 1MHz offset. The proposed FM-UWB transmitter consumes (power amplifier is not included) about 50μW for a 1.2V supply.