This paper presents a CMOS impulse radio ultrawideband (IR-UWB) pulse generator with low power, high peak amplitude and high frequency. A high order derivative Gaussian pulse using LC-Tank oscillator generates a pulse for the 6-10 GHz IR-UWB transceivers. This pulse PSD fully complies with the FCC spectrum mask. The pulse generator was designed and fabricated using 90 nm CMOS technology. Measurement results show the die area of only 0.074 mm2, a pulse width of 785 ps and a peak-to-peak amplitude of 324 mV. The average power consumption is approximately 6.7 mW for a pulse repetition frequency (PRF) of 25 MHz and 1.0 V supply voltage.