A 2.4GHz direct modulated 0.18μm CMOS IEEE 802.15.4 compliant Transmitter for ZigBee

This paper presents an improved fractional-N based transmitter architecture, fully compliant with ZigBee IEEE 802.15.4 standard. Operating in the 2.4 GHz ISM frequency range, the fractional-N PLL based synthesizer architecture achieves an integrated phase noise of 2.6 deg rms (250 Hz - 1.5 MHz). The transmitter error-vector magnitude (EVM) for MSK modulated signals is 5.3% with an output level of approximately +4 dBm. This transmitter is incorporated in a single-chip RF transceiver providing a complete antenna-to-micro controller radio interface.