This paper describes a wide-band sharp-rejection active-RC low pass filter (LPF) for pulse-based UWB IEEE 802.15.4a WPAN applications. Sharp rejection is attributed to the combination of different AC characteristic of three biquads in series. A simple operational amplifier (Op-amp) is adopted to ensure high frequency performance for the designed filter. The LPF is designed in 0.13Î¼m TSMC CMOS process. The cutoff frequency is 380MHz with about 50% of the tuning range from 300-500MHz. The rejection is 40 dB at 600 MHz. The passband ripple is less than 1.5dB and the filter consumes 4.6mA from 1.2V supply. Core chip size is 580 x 700Î¼m2. Â©2009 IEEE.