Abstract: In this paper,an IR-UWB transmitter that cover 3.1~10.6GHz frequency range is presented.It's based on the method that delay generating and synthesis pulses and designed with standard 0.18μm CMOS process.The transmitter realizes a function that BPSK modulation and 5th-order Gaussian derivative pulse generation simultaneously by delays the data and clock signal appropriately and uses them to control pulse-generation cell to generate 0ånd 180°5th-order Gaussian derivative pulse corresponding to different data at different edge of clock.It is beneficial to simplify the circuit structure and reduce power dissipation.The post-layout simulation experiment result show that:when the supply voltage is 1V,the peak to peak voltage and width of output pulse is 200 mV and280ps respectively,its power spectrum density (PSD) comply with the FCC spectrum mask;the max data rate is400 Mb/s and the power dissipation is only 12.5pJ/b.