An Energy-Efficient All-Digital UWB Transmitter Employing Dual Capacitively-Coupled Pulse-Shaping Drivers

• Published in: IEEE journal of solid-state circuits Vol. 44; no. 6; pp. 1679 - 1688
• Main Authors: Mercier, P.P., Daly, D.C., Chandrakasan, A.P.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.06.2009; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: All-digital; Amplifiers; Applied sciences; Attenuation; Broadband amplifiers; capacitive combining; capacitive coupling; Circuit properties; Circuit synthesis; Consumption; Coupling circuits; Digital; Digital circuits; Driver circuits; Electric, optical and optoelectronic circuits; Electronic circuits; Electronic equipment and fabrication. Passive components, printed wiring boards, connectics; Electronics; Energy efficiency; Exact sciences and technology; Frequency synthesizers; IR-UWB; Oscillators; Oscillators, resonators, synthetizers; Passive components; Pulse amplifiers; pulse-based; Ring oscillators; Sidelobes; transmitter; Transmitters; ultra-wideband (UWB); Wideband; wireless; Passive component; Transmitter; pulse-based; Driver; Power electronics; ultra-wideband (UWB); Ultra wide band; capacitive combining; Ring oscillator; Power consumption; RF; Energetic efficiency; Complementary MOS technology; All-digital; IR-UWB; Digital circuit; wireless; Capacitive coupling; Power amplifier; Low-power electronics
• ISSN: 0018-9200; 1558-173X
• DOI: 10.1109/JSSC.2009.2020466

This paper presents an all-digital, non-coherent, pulsed-UWB transmitter. By exploiting relaxed center frequency tolerances in non-coherent wideband communication, the transmitter synthesizes UWB pulses from an energy-efficient, single-ended digital ring oscillator. Dual capacitively coupled digital power amplifiers (PAs) are used in tandem to attenuate low frequency content typically associated with single-ended digital circuits driving single-ended antennas. Furthermore, four level digital pulse shaping is employed to attenuate RF sidelobes, resulting in FCC compliant operation in the 3.5, 4.0, and 4.5 GHz IEEE 802.15.4a bands without the use of any off-chip filters or large passive components. The transmitter is fabricated in a 90 nm CMOS process and occupies a core area of 0.07 mm 2 . The entirely digital architecture consumes zero static bias current, resulting in an energy efficiency of 17.5 pJ/pulse at data rates up to 15.6 Mb/s.