Abstract.A simple method to tune the output pole of a passive mixer is proposed which leads to up to 33 dB improvement in an IEEE 802.15.4 standard compatible receiver's IF section IIP 3 . This method is used in the design of an ultra-low power receiver front-end which consumes just 2.2 mW from a 1-V supply while achieving a SSB NF of approximately 9 dB. The energy-aware architecture allows for a 70 % reduction in the nominal power consumption (down to 0.7 mW) under strong signal conditions while improving the receiver's IIP 3 and not affecting the receiver's input matching. The receiver is designed in a 0.18-μm RFCMOS technology.