A System-on-Chip Crystal-Less Wireless Sub-GHz Transmitter

Philipp Greiner, Jasmin Grosinger, Johannes Schweighofer, Christoph Steffan, Sandra Wilfling, Gerald Holweg, Wolfgang Bösch

Research output: Contribution to journalArticleResearchpeer-review

Abstract

This paper presents a fully integrated system-onchip wireless transmitter that has no need for an external quartz crystal frequency reference. Instead, a nontrimmable LC oscillator (LCO) is implemented, operating at a fixed frequency of roughly 3.2 GHz. This LCO serves as the accurate frequency reference of the transmitter and is used to derive a frequency in the sub-GHz range for wireless applications via a fractional phase-locked loop. The digital functionality required for the frequency generation and thus for the wireless operation is performed by an 8-b microcontroller. The calibration data as well as the application specific firmware are stored in an integrated EEPROM. An initial frequency accuracy of ±52 ppm over a temperature of -20 °C to 85 °C is achieved using only two temperature insertions for the calibration. The device covers a continuous frequency range of 10-960 MHz and provides an ASK and GFSK operation. A low harmonic power amplifier was implemented to overcome design issues due to injection modulation effects. The chip is implemented in a 130 nm standard CMOS process and constitutes a new approach for a fully integrated wireless sub-GHz transmitter that is competitive to state-of-the-art quartz crystal-based transmitters as well as to already existing crystal-less architectures.
Original languageEnglish
Pages (from-to)1431-1439
JournalIEEE transactions on microwave theory and techniques
Volume66
Issue number3
DOIs
Publication statusPublished - 14 Sep 2017

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ASJC Scopus subject areas

  • Electrical and Electronic Engineering

Fields of Expertise

  • Information, Communication & Computing

Treatment code (Nähere Zuordnung)

  • Experimental

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